How can I help him:(?

If he says that right now you can't help him, give him his space. But when you see he is down be there for him, ask him if he wants to talk, if he doesn't you need to leave him, and maybe just being with him is enough. Like I said ask him if there is anything you can do like you have been, but at the same time don't over do it. As long as you show concern, and try to throw his mind off things when your with him, then all should be fine. Hope this helped good luck.