My dad ruined so much of my life, abusing me verbally and physically until I...

moved out at 21. He is either in denial about it, or really doesn't remember it, but I despise him so much. My mom even stood up for me until I was 15, then he started to lay into her...so she stopped, and just let things happen. The last few years he's gone to therapy for depression. Nowadays he asks me constantly if he was a good father, and if he treated my sisters and I the way he should, and I don't have the strength to tell him he was an ass. Just when I had worked up the courage to confront him and join his therapy, he was diagnosed with Parkinson's. So I didn't. I feel like he deserves it, and hope he feels useless and helpless for the rest of his life. Maybe die early and give me a chance to repair my relationship with my mom. It makes me feel like a terrible person, but at the same time I'm happy he's getting his just rewards.