How to cope with these family problems?

My family has always been very close, but lately it's become very dysfunctional. My mom has left her 2nd husband and moved in with a friend. They're not divorced yet, but they're not together either. She's started dating a black guy, which I have no problem with, but my grandfather is very racist and won't acknowledge her anymore. My brother and I are living with my grandparents and my half-brother is with our step-dad. We see our mom all the time, but she's very upset that my grandparents continue to include her ex in family events and never even bothers to invite her since she's left. My aunt is mad at me and my brother because she thinks our mom is being selfish and ignoring the family, but the truth is that she;s tried calling but they won't accept her until she leaves her black boyfriend, which isn't going to happen in the foreseeable future. I'm torn. I want to complete school at my current location, but there's so much drama that I think I'm going to have to choose between my mom and the rest of my family. I'll certainly pick my mom, but I wish I could help fix this mess...