Wow? These people are in college? This seems so silly!

As for your brother, I imagine he's coming to you because he can trust you. I know you're aggravated with him because he can't (or won't) resolve the situation on his own, but I do think it's cool that he trusts you enough to come to you for help.

But this is a situation where you really can't help. He needs to talk to an administrator about this if he really wants anything done about it. This seems to be getting out of hand, and the only one who can stop it is him. He needs to avoid these people, but report it through the proper channels.

As for you, just tell him you want to help him but he needs to help himself. It's up to him what happens now, and how this gets resolved.