Starbuke, I'm also having problems with my mother so can relate to what you are saying.

There are similarities with your experiences. In my case, the unacceptable behaviour isn't because of old age/illness. She's always been a difficult person. Disagree with her/be your own person at your peril!

I agree, distancing yourself is right thing to do. Self-care is very important; you are not here to take her unacceptable behaviour.

My mother is a coward. She'd rather jeopardise a good relationship with her daughter because she can't take issue with those who have caused the problem, namely my aunt (her sister) or my brother (younger/favourite child).