I think the title you gave to this thread says a great deal. It might be something that you just have to face as a reality that isn't going to change. I don't think you ever will be your brother's top priority. Had you been wanting him to be your best friend? Maybe he doesn't want to be. Punishing yourself with cutting and drinking won't alter anything. Do you have friends, or relatives you relate well to? It's actually pretty normal for a young guy to prioritize a girlfriend over a sister. Eventually, he'll select a mate to build a life with. That's not going to be you. You will be on the periphery of his life . . . not in the center.

My brother tended to want me to be his best friend, and even wanted us to live together as adults. He was failing to make normal connections to others. I was very sorry for his loneliness, but I couldn't be the solution to his problem.