JAD AG--Surprising that you're encouraging him to go back to swimming! My parents always told me they wished I had stuck with basketball, because basketball games are way more fun to watch than swim meets.
Besides what Spicewood said, there are other things to keep in mind--
I would definitely get him involved with year-round swimming. Even if you don't want him doing USS and HS at the same time, you should still have him do club for the HS off-season (aka long course USS). Only way he'll have a legit chance at scholys.
Keep in mind that good swimming schools are often good academic schools (See Stanford, Michigan, t.u., Virginia, etc.) and swim coaches, like other coaches, are usually pretty good at getting kids in when their applications might not otherwise warrant admittance. Hidden perk to making a team, even if no scholarship is offered.
Even if he can't get a swimming scholarship, the coaches will often work with the financial aid department to get him a good amount of money if there's a need. I know often getting an athletic scholarship is often a point of pride for kids/parents when they don't even really need it, but if they do have actual need for assistance, they're more likely to get it as an athlete. Some places, like A&M, offer in-state tuition to out-of-state students who get a certain amount of scholarships (athletic or otherwise). So if he has any interest in going out of state, even a partial scholarship is worth a good deal of money.
Another reason to get him in a USS program now is so he can see if he can really handle the intensity that comes with year-round training. It would be a shame for him to give up on basketball only to find out that he is burnt out on swimming, or isn't interested in swimming year round.
Shoot, if he really likes basketball, pull him off the highschool swim team, and have him play for the HS basketball team instead, and then put him on a club team to train when he's not playing HS basketball. Obviously, at big schools with good programs, they're not usually too keen to doing both sports at the same time (overlapping seasons) so this would be a way around that. HS swimming is probably less important than HS basketball to getting recruited, so if he shows some potential in basketball, maybe that would be a way for him to try both for another year until he decides which he really wants to do.
[This message has been edited by gobluwolverine (edited 5/10/2009 2:34p).]