What Should I Do with My Fake Brother, Chacha?

He followed his second-married mother to his new home. Met the nominal fake "sister". She has protected him and stood up for him since she was a child. He could only follow her silently. When did sister know his little thoughts? She was a top student, but her father brought a "younger brother" who was weak and a scumbag. I lament life at every turn. Forget it, I can only pamper my younger brother by myself. But what happened recently? I always feel like my brother looks weird to me!