My brother, what if he keeps hitting people when he disagrees with a word?

First of all, you can't just blame your brother for this. He did it to protect himself, because he was bullied since he was a child.

The mistake is that some children lack education now and say something radical to your brother.

What you have to do is to cooperate with the school teachers and tell them this situation, the root cause of your brother's fight. Punish and criticize those children who make trouble.

Then try to enlighten your brother in character. Let him contact more friends, take him out and communicate with him. Let him learn to deal with people and know how to be patient. But forbearance does not mean being bullied by others.

So don't criticize blindly.