Will he send me a message?!?

It's just possible that he is flattered by your attentions, but since he told you to stop following him I think you have to respect that. He knows who you are now, and that you like him. He might talk to you one day, but maybe he just enjoys the ego boost of having a fan. Why not ask your brother if he can subtly talk around the subject and find out what is going on. It could be, unfortunately, that the guy just finds it entertaining to know you have such a crush, and that's why he and his friends smile. But it could also be that he's beginning to find you attractive. I think asking your brother to find out which of these it is would be a good idea.