Mam, just to clarify, rising freshman as in will be attending college for the first time next Fall, correct? Is son a P or position player? Much of this will depend on what league he is being placed and what the playing time arrangement is. Also, as Bob said, what are his other options?
Pro's -
-head start on playing games against college players (depending on league) can do wonders for confidence and preparation for freshman year.
-he will likely be assigned to summer program the next few years and this will acclimate him to the process.
-many summer college programs have access to fitness facility and at least many of the meals are included, so that cost can be largely recuperated.
Con's -
-your boy won't be home for summer and he probably won't be the next few years either.
-If he is a P, it can be wearing on the arm and he will want to be fresh going into his college fall season
-more difficult to work and earn money (depending on league) over summer.
-he will have to get used to living away from home three months earlier than planned, possibly with much older kids and without the focus of schoolwork to keep him "busy".
If your son has a good local option, this is probably something the HC would be fine with.