My ex had a mom similar to that. Not quite as manipulative but manipulative none the less.

My ex was dealing with forcing her mom out of her life for similar reasons as you, but was beginning to open up to the idea of talking to her again.

She very suddenly got a call from a hospital notifying her that her mother was close to death. A few hours after she got that call, her mom had died.

I understand the pain your mother has put you through is unforgivable in some respect, but if she does happen to take her own life, or she happens to die from drug and alcohol use (heart attack, cirrhosis, etc) you will kick yourself for not trying to reach out one last time.