My(23M) sister's(16F) bachelorette party is going to be something unbelievable. What do I do?

My sister is a very sweet and innocent girl. I know her friend group pretty well, and they are always talking about partying. They are a group of really skanky teenage girls (I mean like the type to fuck a guy at school) and when my sister told me that they wanted to throw her a bachelorette party, I was kinda sketched out. They lied to their parents about where they were going and then went to a hotel and got super drunk.<br><br>They want to do the same for my sister. As her brother, it makes me sick to my stomach imagining her with some random guy at a hotel, and I know our parents do not want this. We are from a pretty religious family and we don't really do that sort of thing, so this would be completely out of character for my sister. I know if I mention it to our parents, my sister will hate me for life. What do I do here?<br><br>TL;DR!- skanky ass teenage friends want to throw my sister a party and get her to fuck a random guy, I am her brother and am stuck on whether I should tell our parents or not.