Who's prescribing her medicines now, Trip? The family doctor?

Your mom needs to get some help from the doctor who's treating her and get a recommendation to see a counselor or therapist who deals with that issue or find one on her own. Whether it stirs up shit or not, she's not going to get any less messed up by waiting. She'll just get sicker. She can seek treatment for herself and let the people who work with her guide her on how to deal with her father if she has to deal with him at all now. She may simply choose not to pursue legal action against him.

My wife, Birdgirl, will be home in a little while and needs to read this. She has worked as a volunteer at our county's women's crisis center for two decades and knows the steps to recommend because she's dealt with situations like this or taken these calls hundreds of times. There are free and sliding scale services to people who need counseling for this issue.

I just found this number in my wife's folder for when she's taking call at the center. I've heard her give this information to many people over the years, and it's a good place to start. If you can't persuade your mom to call the number, you can call it yourself and find out more, I'm sure. It's the National Sexual Assault Hotline, and it's 1.800.656.HOPE.
Here's the Web link, too. Rape, Abuse & Incest National Network.