I don't want my gf to hang out with her male friend
What is your reason for not wanting your girlfriend to hangout with her male friend.
He smokes heroin and his eyes are always bloodshot. He also is always going to brothels.
Usually I would think this is silly but they guy seems like a drug addict. Wanting to keep your girlfriend away from him is fine and makes perfect sense but you should talk to her to see if she hangs out with him because she's trying to help him get clean. She may be doing her best to get him to stop.
I figured that out after I told her to break up with him.
Well if she is hanging out with him and dating him than you should probably break up with her. She is clearly not taking your relationship seriously if she has another boyfriend.