Yo, so it's not my best friend got my sister kind of pissed off about it. What should I do?

If he's your best friend or he's like a good dude or whatever then I think it's fine. If you know he's like a crappy guy or whatever then it would be an issue. If it is, I say you fuck his mama.

Definitely confront that huh that's kind of weird I don't know I have no friends I'm glad I don't have to deal with this