Of course I'm going to plug U of M. The political science department, of which I am a proud graduate, is one of the best in the country, so even if he doesn't major in it, he can benefit from it.
I never felt like it was such a huge school--even in my largest lecture class that had over 500 people in it.
My parents went to Oberlin. Wonderful school.
There's also Lawrence here in WI. It has a great reputation as a smaller liberal arts school.
Good luck to him!