How can u help some one who is depressed?

my ex bf id depressed and strongly thinks no one cares or loves him ..? how do i help him? hes so closed in and when he gets real close to ppl he just pushes them away ..his friends have tryed to help but hes like a wall , and really doesnt open up that much. .. and my friend angelas tried to talk to him and be a friend to him but he just wont budge .. and his friend asked me to talk to him and tell him i care about him and wants to be friend and .. pretty much how i feel, but even to talk to him im kinda freaked out cause last time i talked to him he got mad at me .. and yeah later after that we kinda broke up but i dont know why .. neither dose his friends or anyone but him ? >< so yeha u know how to help him