Agree with the others, pick the school and academic program, not the coach. The question to answer is, if football does not work out for whatever reason, is this where you want to be?
A few others, football related:
Beware of coaches that are used car salesmen.
Beware of coaches that have high levels of turnover among their assistants.
Rosters of current and past seasons are available on the schools' athletic web sites. Take a look and see how many players dropped off the roster after their freshman, sophomore, junior seasons.
A few others, academic related:
What are the predominant majors for the football players?
How many players have chosen the same major as what your son will choose and how have they juggled the academics?
Does the football program have mandatory study times?