I just wanted to say I'm so sorry about your situation. My own stomach tied up in knots reading your post.
Take care of yourself financially and legally in every way possible. As you've clearly illustrated, she's not capable of making any sort of responsible or rational decision. Most importantly, take care of your mental health. Get to Al-anon and get a good therapist. At the end of the day, we can always eventually recoup or write off the loss of $$$ or assets but not our emotional well being.