Does my mom need to know

So my brother is engaging in reckless behavior like sneaking out. I’m really concerned as he’s still seventeen and he is a young black male so that’s adding to the concern for him being out late at night.

Other reckless behavior is that he’s making sex videos with his gf (yes the girl is aware of the videos). My mom is not aware of any of this.

I don’t care that he’s having sex as that part is his business. I made sure he knew to use protection and that he should get tested regularly. As a sister I offered him a listening ear so it has been a lot to take in knowing my little brother is doing these things. I just don’t want anything bad to happen to him cause then if feel guilty for not saying anything, but I’m trying to give the best advice I can to him to be wise in his decisions.

What would you guys do?

Edit:

How do I tell her? I want to make her aware I just don’t know how to go about it.

She gets quite defensive when someone criticize her parenting. Then she starts blaming me for their actions when I don’t live in her place anymore. (Haven’t lived with her in three years).

Update:

I told her and my brother hates me now. So there goes that sibling relationship. He thinks he’s living life by sneaking out , smoking weed and having sex. He literally hates me now and my mom told him I said something.