Hi, Eabtrees, and welcome to PC.
I know I wanted to help my mother, but I knew it wouldn't happen. She drank until she was diagnosed with terminal cancer. I don't know why she stopped then. It was her escape from reality. It sounds like it's your mom's escape too. It also sounds like her family doesn't want to face the reality either.
It's hard to see your parent self-destruct but they are the only person who can save themselves. All you can is take care of yourself. I don't really have any other advice. Maybe find an Al-Anon or ACOA meeting nearby. That would help.