Sadly, it sometimes becomes necessary to stay away as much as possible if not completely from toxic parents.
Both my husband and myself have to do this and are much happier. My parents are not keen to stop contact BUT I limit it as much as possible. They are controlling and completely into Watchtower land and control. I think that is why so many parents 'like' the WTBTS because it expects and demands respect and obedience even when it doesn't deserve it and even when it should not get it and parents who are toxic want the same, unquestioning obedience. Staying 'in' is a means of controlling the rest of the family.
Once you no longer 'play the game' they have no control over you at all.
The answer? Don't play the game. Just walk.