How should I stop him from being someone who keeps blaming himself?

Hey… Long time I didn’t ask advices from here right..? Now I need one. There’s this guy who is really slow. I didn’t realize I like him until last few weeks ago. When we met, both of us were really on good terms.. But now, it seems like, our distance are going further? He’s beginning to ignore me. He is just beginning to get more problems such as he’s thinking he’s a bad guy. Then he goes on blaming himself… So when I chat with him, he’ll say ‘leave me alone’

I’m not asking for love advices. What I’m asking is, how can I make him stop blaming himself and start moving along with his own normal life? He was a funny, loving and caring guy. But now.. He blames himself that he’s a bad guy all because when we played basketball, he acts like a real devil. Yeah, he loves playing basketball. Sometimes he push some of the guys there. But when he isn’t in the court, he’s really nice! I swear!!

I just don’t want him to be emo.. Or moody. And moping for the rest of his life. He seems to stop being himself.. How should I stop him from being someone who keeps blaming himself?