Okay, so one of the guitarists in my band and also one of my best friends, Eric, has entered into what me and the other guys are calling a 'disastrous relationship.' He asked her out after only knowing her for a week! They've been going out for about 1 week now. But that's not the problem. The problem is that everyone knows that she sleeps around with guys like no other and is one of the biggest (excuse the language) whores in the school. She's also what we call a 'pothead'. Eric is a really good guy and if he knew all these things he would NOT have gotten into this. Eric was unaware of this though because he just moved here a few months ago and so now he doesn't believe ANYONE when they try telling him about her. He says that we just have to stop believing everything we hear, even though we know for a fact she sleeps around and just wants to get in his pants. He's already threatened to leave the band after we just tried talking to him about it calmly. We're stuck and don't know what to do. We really care about Eric and know this girl is NOT for him and is just going to end up hurting him. What should I/we do???