My brother he doesn't feel good with his look and doesn't want to go out a lot.

My brother always has a feeling that he is ugly and people will judge him about his appearance. He doesn't have friends I mean just one friend that he meets him very rarely and he doesn't really like to go out. I mean he is lazy about that, he just stays playing with his phone all day long. Nothing else! He is 20 years old. He doesn't take life seriously, the only part that he takes seriously is his appearance and what people will say about him. He oftes thinks that people hate him or mock him. And he get upset very easily. I just want him to be active and go out more. When I try to talk to him he says that he Will take better grades etc but nothing. He doesn't even learn in school. Just stays all day. And he gets angry sometimes with me when I try to help me. Please any suggestions. How do you call this situation? What do you think about my brother? Help me please I feel worried.