Is he good?

I have a classmate let’s call him DBD. (Not his real name) He is sometimes very frustrating, but he also has great ideas. He’s smart, to be honest. His petulant behavior is frustrating. That’s all I know about him. I was also scared of him because he would get angry at my classmates in our GC. So much that I obeyed him. One time we had to make a song; he was the leader, and I was in his group. Then he texted in the GC “I have the worst team” That hurt since I was there… And if he would say something like just butt in, like to say what’s happening? He would reply Stfu (if yk what that means) I told my mom everything about Brix my mom said “We should report him” but I told her no. Since ik why he was acting the way (kinda stalk don’t judge pls) Well I can’t blame him. I think he had rough memories. So what do you think is he just bad bc of his childhood or he just wants to be like that?