The Freshman Year Experience

You have just joined a fraternity. You are at your chapter's first social event with a sorority. This social event does have alcohol. During the event you notice that one of your fraternity brothers has been showing a great deal of interest in a female attending the event for the past hour. They seem to be having a good time, but it is clear that the woman has had too much to drink. At one point, your fraternity brother walks by you and you hear him say he is just going to get her “one more” and “that should be enough”. A few minutes later, you see him put his arm around the woman and start to lead her out of the event. What do you do?