Allegiances aside, if you like college and love sport in general, I can see stayin. However, if your goal is to have a long professional career, wouldn't one want to strike while the irons hot and focus on your goal while you're at your peak physically?
I just hope his "inner circle", as knowledgeable as it is, is leaving the important part of the decision up to him.
There is plenty of precedence for a kid to get drafted and play football in the fall and report to his rookie club the following season. Surely he'll get an insurance policy to cover for injury but if he really wants to play football then he'll play That's all there is to it.