Sorry about your mother, I lost my father last year to cancer (and found out via my sister, and I live halfway across the world).

This event is actually how I ended up severing contact with my sister altogether... My mother has bipolar disorder, my sister, and my father had it. I'm BP2 and my sister is BP1 (like my father was) . She has never seeked treatment and thinks that mental health problems are made up (despite the fact that she was in the hospital several times, and often made attempts on her life). So one of her last lows (when I was on vacation there...) forced me to step out of her life. My father died a few months before this happend, but yea, without treatment it can spiral. This has been going on for 20 years or so, so it's not like I didn't try to reason/help.

She has a son now and my grandmother lives with her, so until she gets herself together, I am also excluded from their lives. It sucked at first, but it's better for my health to just leave things alone and watch from the outside.

I get updates from my mother, she now bought a house (first viewing, ever), quit her job(awesome to do when you bought a house), and keeps having parties when she doesn't have the means. So it's going... Okay?

Okay this doesn't really apply to your situation too much, but I wanted to share how it can sometimes get, and that I understand how it is. I say try and work things out with therapy or something, otherwise, what happened to me is extreme and probably far from necessary with how your dynamic is.

Sorry for the constant editing, things keep popping into my head.