I dont know what to do

My brother doesnt like me to sit with one of my friend and talk with. I dont know why, but whenever he sees me sitting with him he is about to punch me or him in the face. I dont want to have an affair or anyting with him but we always talk about...

classes, school. He is a nice guy I dont want to make him sad from me by saying I dont want to talk to you anymore. I already told my brother that when ever im sitting in the library he joins me not me going to sit with him, so then I can't tell him get out of my table it is rude. I can't understand my brother and I dont know how to tell my friend that there is a problem dont talk to me anymore. I dont know what to do.

Can your ask your brother? It would help if he would try to explain his behavior. The only thing I can think of is that he wants to protect you from this guy (ex.:is he older then you?) and so he acts like he does. The only way to truly resolve the question is to confront your brothr about it and find out what's up.