Rock, Smaller schools do have less funding and staff to be as agressive early in the recruiting year. However, they are also recruiting right now. All levels have "lists" of players and they generally start at the top of the lists with their recruiting.
My son was also a kid who was recruited by all different levels in HS. He received calls though beginning July 1 from DIs and I believe the first NAIA called in September. However, come December and January, the NAIA and DII calls picked up drastically. He never heard from a JUCO until December of his senior year.
I would suggest that your son get his fall schedule out in the next week followed by a phone call to those schools that expressed interest in him. The phone call can be used to let them know he's sincerely interested as well as to follow up and see if they received his schedule. If the phone calls don't pick up, he will need to be more agressive this winter and perhaps ask for some workouts. DII, JUCO, NAIA can all work a player out. I suggest doing this when there are players for the school on campus. Speaking with the current kids can provide a lot of insight into a program. Plus, you get a peek at some of the chemistry within the program!