Narcissist mother...what to do?

The "obey" thing ended when you became an adult on your own.
The honor thing: all this means is some respect for their opinions - it is not necessary to agree or to follow their advice.  And being their doormat is NOT honoring them.

Your mother sounds like my very narcissistic mother. She moved three times in two years. Her only child, me, had to pack and arrange each move. She also became meaner and meaner to me each time. At the end she would tell everyone who would listen how awful I was. I started helping her when my father died and responded to each need. I even put her insurance on my credit card because she wanted to cancel it. I handled all her transportation, appointments, trips, bills, etc. When I paid her bills I was stealing her money. She called at all times, night or day. But no matter how she begged, I would not let her live with us.
She took my health with the stress she caused, but it would have been much worse if she lived with us. I had adult children with real issues and disabilities. I also had a full time job, although I had to retire early because of the health issues. Stress kills and causes horrible diseases.
My mother was like yours at the start of her decline. It was dementia, and even her favorite doctor did not catch it at the start. Do not let your mother live with you. The meanness will only get worse and eat away at you. Limit your time with her, and definitely tell her you are out of town regularly. It is not easy even if she is in AL, but at least you can still have a life.
Ultimately you cannot make another person be happy. Although I had relatives and others who bought into her nasty fantasies, there were also friends of hers and mine who actually understood. One was a retired nurse and stuck it out until the end, a true angel.
The point to my saga is not to get in too deep. It is not easily undone, and can be very costly in more than just monetary ways. At least tell her sometimes that you are going out of town for a few days. She will never know.

Whenever she says anything that is rude...hang up the phone, walk away, just leave her to be by herself.

you could announce that you will not tolerate whatever behavior she is exhibiting...then cut her off if she continues.

eventually she will decide to either modify her behavior or be alone. Maybe decide to move back to that assisted living.

Set your boundary, announce it, and then enforce it.

ONE time in the past 8 years my husband said, "Gee I finally see your mother acting like a mother." It was when I had hip replacement surgery and she felt badly that I was feeling some discomfort on Easter Sunday sitting in a chair in my living room. Her sorrow lasted for about 20 seconds until she realized she had some other issues that were more important than mine. Like a runny nose or a hangnail.

When my mother gets off on a tirade, I tell her "I'm hanging up now mom and I will speak to you another time when you're in a better mood." When I go visit her in Memory Care and she starts going berserk with whatever is bothering her at the moment, 90% of the time I'll tell her I'm leaving and will be back when she's in a better mood. The other 10% of the time I sit there and try to talk her off the ledge, which never works. We wind up arguing, I wind up yelling, leaving, feeling badly, and the whole cycle amps up again where I'm the Bad Guy and she's the Innocent Victim. See the pattern? No matter that SHE is the one who instigated the whole mess, the goal is to be the Eternal Victim and when I get arguing with her, she's winning. And I'm losing.

So now my husband has developed a Code Word to use when things start going downhill. He speaks the Code Word & I immediately shut up. I've almost bitten my tongue OFF in the process but hey, it stops the feud mid stream.

Sigh. It truly is a giant MESS what goes on with these women, isn't it? Nothing is ever their fault, either, God forbid. There has to be SOME poor slob to blame things on so for now, I guess, you're it.

Take care of you, please. Just b/c your mother got pregnant one night does not mean you 'owe' her honor or obedience. Respect is earned, as well, and not something automatically given to people who choose to treat us badly.

Best of luck.

You must get this book written by psychologist Paul Chafetz called: Loving Hard-to-Love Parents: A Handbook for Adult Children of Difficult Older Parents. It’s on Amazon and a easy fast read. He counsels adult children of parents like yours. Even does online Skype counseling. He has great tips on handling parents with personality disorders. Also, look up How to "go gray rock"...which is a method for handling narcissistic people. Good luck. She’s a piece of work obviously!

You are not going to be able to change her personality.  She is obviously a very negative, unhappy woman.  If you don't play into her "game" then she loses control over you.  I would leave her be and see what happens.  If no one calls her or seeks her out, she will have to reach out to you and when she does, act as if nothing is wrong.  If she starts saying hateful things, tell her you need to go.

Life if short!

Hello 'MyMothersKid', I'm impressed with how respectful you say u are toward ur mother, (& suggest you not 'test ur limits'), by spending 2 much time with her.
Mom's very fortunate to be in such good health, but 2 bad about her personality issues. Please don't let her move in with u, (just help her out in whatever ways u can manage.) It could be a long road ahead for you all...so pace urself!

Let her alone and see how she does. Apparently she has never been happy and takes it out on her children. Don't ruin your life over her issues. If she is in sound mind she will figure out that she needs all of her children and might stop treating you badly. Sounds like this is just her personality.

Would you put up with that behavior if it was coming from a friend? Of course not. You wouldn’t be friends anymore. You can love a relative, but nowhere is it written that you have to like them.

I have a very difficult son. I love him, but I sure don’t like him very much. When he exhibits behavior that I won’t tolerate, I block him from my life. It’s a shame, but it’s what has to be done, for my sanity.

Same thing with your Mother. Stop visiting. Let her calls go to voice mail. I know it’s a hard habit to break, so try it for just 3 days. No contact whatsoever. Then see how she is. She’ll probably be the same, so this time, try it for 5 days, or maybe a full week. You’ll see that manages to make it somehow, without you to kick around.

Stay strong. Remember she can only be mean and cruel to you because you are there to see or hear it.

"Just b/c your mother got pregnant one night does not mean you 'owe' her honor or obedience. Respect is earned, as well, and not something automatically given to people who choose to treat us badly."
AAAAAAAAAAAAAAAAAAAAAAA-Men!

For those who tell us that we *must* honor and cherish this woman who gave birth to us (or a dad who provided for us) most likely haven't experienced anything like this. Perhaps you felt they were a little harsh with you now and then, and got over it, but cases like this are NOT the same. When it is all the time and goes back even into childhood, these people are toxic and we should not let them take us down in the process. Why should anyone honor or respect another person, no matter who it is, if they treat you like dirt? Turn the other cheek, or forgive perhaps, but we should not lay down and let ANYONE walk all over us!

To OP - Keep your distance as best you can. Make yourself unavailable. If/when she starts treating you bad/smack-talking you or anyone else, hang up the phone or walk away if you are there. I probably wouldn't even allow her IN my house, never mind let her live there, but by not allowing her in, you can shut her out. If you meet with her, make it at her home or somewhere else, then you have the option to leave. If she has some kind of medical emergency, certainly you can be there to help out or take care of something for her, but again, if she still behaves like that, walk away.