I think parents do what their parents did.
But some are just crazed child abusers.
Do you want them in your life?
Really love them? If so then forgiveness is a part of love. My ex tryed to strangle me. I got a restraining order. I don't love him now. But I have forgiven him. I think it was a crime of passion. But I wouldn't trust him or care to be his friend.
So you could do the Ben Franklin close. Write down all the benefits on one 1/2 of the paper. Then on other 1/2 all the negative consequences to being part of their lives.
This will help you clarify your feeling and help you to decide.