I'm going to break up with my bf because of my brother
What is wrong with your brother?
I don't want to be related to my brother anymore
You probably shouldn't let your family interfere in your relationship in general, and certainly not in this case.  Breaking up with your boyfriend will not do anything to change whatever animosity there is between you and your brother.
But brother is a total dick head.
It is wrong to blame your brother for your relationship ending. You should take responsibility for your actions if things didn't work out.