A very good friend often sends him short messages, but he doesn't reply.

Hehe, don't worry, I've met it, too. Maybe it's just a moment of anger and I don't want to talk to you for the time being. Then don't look for him. Slowly, he will find that he is not used to it and will take the initiative to come back to you. That's all true, but if he makes up his mind not to continue to associate with you, there's nothing he can do. Thank you for your adoption!