or just start hitting on her, she might stop liking the other dude
Face it dude for you know what would be the answer. I mean text/call/chat her and introduce yourself. And tell her your feelings for her. That's the only way you that make you close to her.
He's leaving in about a week. She's going to be a wreck. I'm just going to try to "be there" for her and see where that goes. I actually wouldn't mind staying as a friend.