I know how hard Princeton is to get into. But it's the one school my mom seemed happy about me choosing, so I put it on my list. But Princeton doesn't accept solely on grades, either. Most colleges won't. In the magazine I mentioned earlier, How to Get Into College 2008, there's an essay/article by an admissions officer (not at Princeton, but one of the other Ivy Leagues...can't remember which) and it mentions that they had a question on their application that was "Ask yourself a question and give us the answer" and there was one student who asked himself "Do you play the tuba" and answered "No". Normally they would have just written him off as a smart aleck, but instead he had great reference letters from his teachers. He didn't always have good grades, but he pushed his limits to learn and he was a nice kid. I'm not saying your friend isn't, but with Princeton having just about an 11% acceptance rate, you can't expect them to take every last one of the really smart kids that apply. If they did, there would hardly be need for a teacher. Also- I don't belive Princeton weighs AP exams.
But anyway, which college did he end up attending?