My 6 year old brother keeps swearing,stealing, and being mean to other kids. He also acts like a gangster and likes that gangster stuff. Why is he being this way? I think he will be really bad when hes older.
Hard to say. He may not be getting enough attention and so is using bad behavior to get it. There may be somebody in his life that's older and acts that way that he looks up to. Some kids just don't have the dicipline they need. He might have seen this behavior in a movie. It sounds like you really care so being there for him is a big part and if you think it's for attention, ignore that behavior and pay attention to good behavior.
He needs to stop watching TV. If your parents tend to swear a lot, try and get them to stop because it rubs off on your little brother.
He's getting it from the people he's around or from the things he sees on tv
I don't know but have you talked to him about it