My Brother Won't Let Me See My Nieces and Nephews

My dad convinced my brother to not let me around my nieces and nephews if I refuse to go to a particular treatment center he thinks is best for me. To say I'm heart broken and furious is an understatement. I was willing to go to one closer to home, but no. it has to be his way or the highway. so now I'm stuck In a different state and will never see my nieces and nephews if I don't do this. I want to see them again. But the fact that my brother wouldn't trust me around them now is changing the way I see him and my family. I want to be a part of their lives, but at the cost of everything? How will a few months change who I am? That's never going to change how he feels about me now. and now that I know that... he will probably never let me around them ever. So what's the point? I don't even want to to try anymore.