I remember you posting about your mom on here. It reminds me of my H's mom. She wasn't horrible till about 5 yrs ago. So he doesn't have the childhood trauma that you have went through. She still had characteristics of Borderline Personality Disorder but not the ful blown delusional, occasionally psychotic stuff she pours out now.
It is not unusual that families with BPDs in them to need legal help. When she first went round the bend she threatened to sue us multiple times. Anytime my H tried to help she would accuse him of stealing to anyone who would listen. It's psychotic and dangerous. She needs so much help but nobody can get near her.
I can only tell you what we do now and I have limited experience but I do understand to a point. I hate seeing what she does to my H.
When I first figured it out, I went on the boards at BPDfamily.com and I understand that there are people who grew up with it like you did and only people with your experience can fully understand. It's kind of dark on that board and I would be careful you don't do it too long.
PTSD is pretty common on there. There are specific therapies for it, I think it's called EMDR. That's where a professional can help you.
Otherwise if you want, PM me and I'll try to help. God Bless you.