Should I tell my brother

My half brothers dad molested me from the ages of 5-19. My half brothers doesn’t know. He now has a daughter who is 6-7 months old. And he watches his kids. 3 boys 1 girl . Should I tell him? I feel it could go wrong in so many ways. what should I do?

additionally my mother is still with this man and she is aware of what happened

It all came out when I was 19 but my brother is a 11 years younger then me. I never told him to protect him emotionally. But now that he has a daughter.

How should I go about telling him…?