My brother is a stranger...

My brother and I haven't had a relationship since we were children. We literally grew up in different places. He was in a lot of trouble growing up, in and out of group homes, jail, rehab. I spent most of my teenage years helping my parents dig him out of some disaster. He has been extremely hurtful to me both physically and mentally over the years. About 7 years ago he was evicted and my parents took him in after not living with them since a teenager (he is now late 30s). He's never left and I am tired of him taking advantage of my parents. My father doesn't get involved, as he doesn't want to argue at his age. My mom is guilt ridden for the way her son turned out. Now about 2 yrs. ago he met a girl online, within 3 mths she moved into my parents house and she is expecting a child in a month. I was told about the baby by my parents not him. I also believe I was invited to their baby shower because my mom asked them to invite me. I am very hurt and upset. I can't stand the girlfriend, I never have had a relationship with my brother and now with a baby, I don't want to upset my parents by being so detached but I am tired of my selfish, leech of a brother who really could care less about me at all. We don't celebrate holidays together, we don't speak or text, in fact when my mom had surgery this past summer she had to come and live with me not stay in her own house because she didn't feel comfortable enough to recuperate there with my brother and his girlfriend. Am I obligated to suddenly be a part of my nephew's life when I have absolutely nothing to do with my brother or his gf? I don't know if now I am being selfish and unreasonable, I just have been taken advantage of and hurt by him too many times that I just don't know what the right thing to do is?

have a talk with family as to how u feel about this,you can always move out and build your life somewhere else,i dont think people will change