What do you do with the anger that is left?

I am not one to hold anger or grudges as the only person it hurts is ME. The person that I would be angry at does not care.
This is more true in your case.
Your Mother was a narcissist and if you let her drive your anger still she wins again!
Don't think of the years that are past...think of all the things you can do now and not have to worry about ...
explaining yourself, defending yourself, running errands, denying your own needs mentally, physically and emotionally.
Take your life back and don't let her ruin what is left.

Anger is part of the healing. Get it out, I have found a nerf bat and a pillow really get rid of the pent up emotions and don't cause damage or a mess.

Use the bat and tell the pillow everything you could never say with each and every wack, let it out and let it go. Do this as often and as much as you need to, it will help you feel better.

Hugs, it is time for you now. Don't give her any more of you then you already have. It's over with her, make this about healing you.

Ten years? True narcissists make their victims lives hell for their entire lives. You wrote that you,"spent ten years making a narcissist happy." If your mother was abusive, which is the center of narcissist existence, then you were abused your entire life, let that be your motivation to break away from current toxic relationships.
Perhaps avoid using "could" or "should," since victims of abuse have their decision making capabilities stripped from them. As a survivor, I learned to never doubt my decisions, sine they were made during a different time, under a set of different circumstances. The word "should" caused anger, since should = not going to change. I "should have" or "could have" are the most dangerous, since the circumstances in your life were different during that "should have" or "could have" realm. To rid yourself of anger, understand that you were conned into thinking that the abuse was your fault, which helped distroy your ability to make basic decisions; since narcissistic abusive Asshats, scream at us no matter the decision we make. Evaluating results, concrete results of those decisions helps to negate the screaming for making the decision. Now that she is dead, you'll connect more dots in your memories and will understand why weird things happened. Anger fades, when you have abuse removed from your life. It takes time, focus on the future, and upon learning how to navigate life with M.S. Auto-immune incurables seem to occur within bodies of those who have been abused, by douchebags. Personally whilst in the midst of a narcissistic cesspool, I had a stroke. I'm exiting the anger phase, since now, their douchebaggery has finally faded, they were exercising their narcissistic manipulations while I was hospitalized, and continued through my move into an old farts home, I'm 48...old, yet still cognizant? My counseling degrees are filled with recommended resources found on Amazon: two books, collectively provided more insight than my M.S., and M.Ed. Counseling Psychology degrees (formal education): 1). Why Does He Do That? by Lundy Bancroft 2). Emotional Blackmail by Susan Forward.

I'm guessing that -->you spent more than 10 years dealing with psychological abuse? Following other recommendations--> the idea of finding a counselor is excellent, More specifically a trauma counselor, or a counselor familiar with psychological abuse.

I'm so sorry for your chronic condition. MS is a devastating disease.

"I spent ten years making a narcissist happy." I understand the feeling. Except my narc was never happy, never satisfied. I sacrificed childhood and the best years of my adult life trying to appease her. I was duped.....and it doesn't feel good. The negative feelings don't always pass with the parent or the parent's loss of cognition.

Mom is still with us. She has dementia and mostly cannot help what she says or does any more. But I still find myself angry at times for losses that can never be "put right." Loss of innocence. Loss of self, time, and peace of mind. Ruined chances. Ruined relationships. Decades of anxiety and depression.

At times, self-loathing nearly ate me alive. I played right into her hand. As a kid and young adult, I was her enabler, believing everything she said, because moms never lie, right? (sarc). As a child, I couldn't help it. As an adult, I should have got a clue.

Keepingup, don't let your mom rob you from the grave. Whatever time you have stretches out before you. Live it. Resolve to be happy, free from toxic feelings. A life well-lived may be your compensation. (((Hugs)))

I'm so sorry. I know that feeling and went through almost the same situation. I threw myself a little bonfire party. In a bucket of sand LOL. I wrote down all of the things she had saddled me with being on slips of paper: Stupid, selfish, lazy, uncaring - and of course her favorite phrase of 'you'll spit on my grave'. She handed that one out like Pez because it worked on the whole family.

Anyway, I lit myself a little fire and took those slips of paper and I burned them. I forced those perceptions of me out of my life one by one. I had to. I literally thought I was going to die before her from stress. I could feel the rage ebb with every single one that burned. They had no power over me anymore.

Then I took one piece of paper and I wrote in big red letters; FREE!! I keep it in my wallet and whenever I look back and I'm tempted to feel guilty, or useless, or a disappointment it's a huge reminder to let go. It's not your disease. She created it and she owned. Let it stay where it belongs.

Dear keepingup,

I'm so sorry, I know hard it is to be the primary caregiver to a parent that doesn't appreciate you.

The anger is real. I think we all secretly hope that our parents would express some love, acknowledgement and validation for our efforts. So many daughters give their time, their efforts, their money even to help their parents.  Its hard not to relive that all even with their passing.

Please know you are not alone. There are many people who understand. And if you want maybe consider going to grief counselling or joining a support group in the community.

I can't tell you how many times I visited this forum for support and encouragement after my father passed.

I hope you will allow yourself to feel whatever you want and know its only natural and normal after such a long journey with a parent.

Thinking of you.

Volunteer.

Give to others. Give your time, your expertise, your money. Help those who are less fortunate.

Move forward —-don’t trap yourself forever in your sadness from the past.

I think anger is part of grief, or so I've read. We still grieve a parent, even when they are narcissistic, (Hell, we spend our whole lives grieving the absent parent bond). Your anger cud be from living life without that precious bond, how it affected everything for us, & now it's over, but no closure. I feel for you, & will tell you how I heal day-by-day: I accept God's sovereignty in my life, & His ability to give the love & security we missed out on. That's a gaping hole that no therapist can fill. Just sayin'😔.

Some ideas about the anger. 1) It never goes away. 2) It fades with time. 3) Psychodrama can help.

I took part in a psychodrama group years ago, and this is how it goes. You, the playwright, choose the characters from your problem, then nominate from your little drama group who plays them as actors. Perhaps just you and your mother, standing up in front of your little audience of the rest of the group. Then as you playing yourself, you say what you want to say to your mother – what you usually said, or alternatively what you never said while she was alive. You walk off the ‘stage’, and this speech is repeated by the person who plays you as an actor. You then play your mother. You answer as your mother, the way she would have dismissed it, yelled back, what ever you know she would have done. Then you walk off the stage and your mother’s player repeats the same lines you have just ‘written’, while you stand and watch. You then model how you want to reply, stand back and watch your player follow the lines you have given. Next you stand in for your mother again, and reply the way she would have done.

All this is quicker to do than to describe. You, the playwright, are providing the lines for your mother and for you. You can do it the way you actually did in the past, and you can do it again yelling your guts out and saying the things you wished you had said. Your mother can reply the way she usually did, or you can write the lines for her to break down and apologise for her bad behaviour. And you can watch it all, played to your script by actors playing the parts for you and your mother. If other people in your group get into it, they may want to ‘play it again Sam’ with their own suggestions for how to respond, and that can be useful too.

The recommendations are of course for an expensive session run by a professional, but you may be able to manage it with a group of intelligent friends (who may then want to go on with their own dramas to model – mine were about dealing with an employment situation). It can be very helpful: first you can say all the things you never said (and it is amazing how real it becomes – yes you feel that you are talking to your mother), and second you can watch your players acting out your live dramas, while from outside you can form a different take on it. It is also quite good fun to play around with this.

If you are left with anger that you have never been able to deal with, see if you can find a way to go through the sequence I have just described. Standing up and saying it all is a real help. The most dramatic example I was involved in as an actor (complex family), turned out to be a problem with a parent who was dead! My own ‘drama’ was to model how to handle a living situation, but it works for the past as well.

And if all that seems like rubbish, go back to 1) It never goes away and 2) It fades with time.

Of course you are angry - you have been caring for a self centred and unpleasant person not only for the last ten years but for as long as you can remember. You do not have to feel guilty about being angry or for any other emotion you feel including hatred. You didn't ask for this and you have been made to live through it. BUT you are free now. You can try counselling - or I would personally try hypnotherapy from a properly qualified hypnotherapist, not an "I promise to make you feel wonderful" one. Or you can simply accept that this person has caused great problems in your life but you are not going to dwell on them or try and give them reason. You don't need to so you aren't going to. Every time you get a negative thought tell yourself it is not important and do something to take your mind off it. Book a holiday to do something you have always wanted to that would have been disapproved of, get a dog and enjoy walking and the freedom to do it - anything that YOU want and have wanted. She cannot hurt you anymore you have total permission to do exactly as you feel and want to.