Need more patience, how do I get it?

Joyce4me: Imho, I do NOT advocate moving your mother in with you and your boyfriend. Your mother should find facility living - or actually you should do that for her as she has dementia.

There is a lot of good advice here, so I won't repeat it. Understand that your patience will not improve until she starts to relent. Unfortunately, as her dementia progresses, she will probably commit an act or have an accident that will force your hand. That could still occur, even if you moved her in with you. You could start by having different people to check in on her. That could be a sitter, friend or "housekeeper". In the meantime get her affairs in order and prepare to find her a facility. My mother fought me " tooth and nail" in her fight for independence. After she broke her hip, I was forced to place her in AL. After 4 mos., my sister selfishly decided to take her out of this environment, but only during the evenings. I still paid for AL (as daycare). But, this only lasted for about a year.... they fought constantly! It was a battle of wills and this was just from the hours of 5:00 pm to 7:00am!
I wish you the best and know that having other siblings involved is not always a blessing.

I too am dealing with the same issue with my mother, who turned 90 today. She has been diagnosed by 4 different doctors with severe cognitive impairment but will tell you no doctor told her that. We have printed the reports over and over and she throws them away. We took her car about 2 and half years ago and she has never gotten past that. Every day we get dozens of emails saying the exact same thing. "No one told her she couldn't drive, we are bullies and stole her car." She mostly refuses to participate in any family events and is depressed all of the time. She lives alone and certainly should not be, but unless we get conservatorship we can't do anything. We have POA and it is not enough to make her go to a memory care unit.
Sad but I keep hoping she will get worse and she won't continue to send the hateful emails.
So I don't have any advice, I have completely run out of patience with my mother. It is difficult for me to even want to visit her. Fortunately, we have a woman who checks in on her a few days a week, but it isn't enough.

Patience is a difficult virtue to develop later in life, I think. But it can be accomplished. One key is “expectations”. When our own expectations in a matter are not met by the other person, we get impatient or angry or discouraged because our own expectations (or our belief that we have a solution that another should agree with) are rejected. Frustration ensues, and we think we must convince the other person to change to our own point of view.
So then it makes sense to examine our own expectations, to re-examine what we are attempting to impose on another person’s life, a life they HAD BEEN in charge of for all of their years. And then make gentle changes according to their preferences.

And, even with a person with dementia, it makes sense to examine THEIR expectations, or just their responses, if possible, because that can teach us about how to better communicate and reach them in some cases.

Example: “mom, you SHOULD eat breakfast, lunch and dinner”.
Instead, specific questions or suggestions: What do you like to eat? Would it help to have small plates prepared for you, etc. You already know those things, but my point is, instead of saying “you SHOULD or you HAVE to…”, it might be more productive to enlist their input so they feel ownership or investment in the decisions that impact their day to day lives. If they can’t, that’s another problem to solve.

These suggestions here are probably already known to you and I hope I don’t sound patronizing, but, when we are busy and sometimes swoop in to quickly check on mom’s welfare, we sometimes forget how we sound in our hastiness. Or, in our frustration and emotional panic, our responses are not thoughtful or empathetic (or correct).
I am trying to remind us to relax a moment, be present, be WITH our loved ones. To listen, even if you don’t/can’t agree. Be silent regarding your judgments and criticisms. Instead, say “how can I help you today”? Show them you are listening. They can tell.
Demonstrate love, by loving gestures and small kindnesses.

You know how important it is to not feel powerless.
Best of luck in your decisions.

Please, please do NOT allow her to live with you if she has dementia - it will get worse and YOU and your entire life will be torn to shreds. This behavior is intolerable and no matter what you do or say, it will only get worse. Don't get involved in her care - it is just too much. Place her and be active with visits and calls - let her be cared by those who are trained for this - not you.