D18 was a Swat athlete. Your son will have no problem meeting others and being social beyond the team (if he wants). I think it’s easier to be more involved than at a larger school, as there aren’t so many people doing things. The school is very open and accomodating. My daughter sang with the choir for 4 years and was involved in a few other things on campus.
Post-graduation, my D sees former Swat classmates every month or so in various and sundry places…none of them are athletes…all friends from her freshman dorm or classes.
The one thing that I would be concerned about is your statement that “he’s as good as in”. He is still going to have to apply, and if you learn anything about coaches and LAC’s it’s that they don’t carry nearly as much weight as you think. At Swat…the one exception right now might be (maybe) men’s basketball…Landry probably has the pull to do that. Even if it is BB…be careful.