I've not heard of the exact scenario you describe, but perhaps this can help:
If your son graduated from high school in 2003 or later, and if he was a qualifier through the NCAA Clearinghouse, he DOES NOT need an AA degree to transfer. If he was not a qualifier through the clearinghouse, he must earn his AA degree to be an eligible transfer.
The 48 hours is, roughly, the number of hours necessary to meet the 40-60-80 rule. If he was a 2003 grad or later, he meet meet 40 percent of the graduation requirements of his specific major by the start of his junior year to be eligible. If he has taken a mostly normal schedule of JUCO classes, he should be able to meet this standard because he will fill nearly all of most schools' general education requirements.
The AA degree does not, as far as I know, matter when it comes to the 40-60-80 rule. So he and you should look into the would-be requirements of each school you consider before you make the deal on a transfer.