I'm going to tell my sister's friend to stop adding so many men on snapchat
Why does he add so many men on snapchat?
He does it because he's a man whore
Even though you shouldn't judge people for dating around, it is okay to let them know how it looks to others. It could help them realize what others think of his behavior before they hurt his feelings by saying something about it.
It doesn't matter to me. The guys he is dating I do not care about.
It is fine to let him know about your opinion. Just also let him do what he pleases as well. There is really a way to tell people these types of things, and if you do not do it correctly you can really escalate a situation.