Not sure what to do.

I havent talked to my parents or my sisters family since summer. They are always starting arguements and just being dysfunctional. My mom kept my abusers pic on the wall even though she knew what had happened. I feel like people that hardly know me know me better then my parents and I almost 40. They never come around but will have assumptions about me and my family. Well I just learned that my dad has COPD with emphasima. Does anyone have tips in dealing with difficult family.