I may digress from what other people have said, but I honestly feel like there is way too much drama here for what actually occurred. It was a drunken kiss. Not even a kiss, because he didn't kiss you back, and made sure nothing happened. So I legitimately don't understand what all the fuss is about. If their relationship is going to fall apart because of an almost-drunken kiss, one he didn't even reciprocate, they don't have a very strong relationship, and it's not your problem. I assume y'all are adults, if you're drinking. Talk about it like adults, openly and honestly. This doesn't have to be the end of your friendship.