I wouldn't put too much weight on the Yale and Harvard degrees. My sister was on the Harvard faculty for awhile, and she said everyone knows about the "happy bottom quarter." They are the students who are happy just to pass. Their parents are alumni, often very wealthy and famous alumni, or they would never have gotten in. (She also said grade inflation is insane. Nobody wants to give a student a C, let alone a D or F, because their last name might be Rockefeller.)

There's another possibility as well. Maybe he was once very bright, but fried his brains with drug use. It's pretty well established that long-term abuse of drugs and alcohol can cause permanent impairment.