1. First of all, you should ask your brother why he bullied your sister. If your sister started the storm, you shouldn't just scold your brother. You need to know what happened and judge right and wrong.

2. After knowing the real situation, if my brother is wrong, he needs education and guidance, and can't bully his sister. Boys are men. It is wrong to bully girls.

If it's my sister's fault, I should tell my sister that my brother is older than her and belongs to the elder, so I can't bully him.