I’m not sure how to feel!!

So I just found out my baby sitter was gang raped at a New Year’s eve party and her boyfriend took her there he passed out drunk on the couch and she was drunk, but doesn’t know if something was put in her drink or not. I just don’t know how to feel about her dating this guy anymore I just don’t know how something like this could happen! No this has never happened to m personally, but it did also happen to my other little sister I am so heart broken that this has happened to both my sisters!! I asked her to come over after she left the sheriffs office, but he is with her and all I want to do is go off on him!! My sister isn’t acting like anything really happen I just wonder if it hasn’t clicked in yet that something happen or I hope this hasn’t happened before!