For what it’s worth…
We had planned on a PG year and then Covid changed plan and my son reclassed and repeated 11th instead. But I know many boys who did a PG year. All athletes but NOT all recruited or even planning on playing in college.
Here’s my $.02. If you think your son is not ready for college, you are most likely correct. Going to college and struggling and/or having your parents overseeing you like you’re still in HS can be demoralizing. I know many boys who ended up in this situation and dropped out or took time off to regroup. It’s a difficult experience.
My son was substantially more mature and ready at 19 than at 18. Some of that was the 1/2 step of 2 years at a really good fit BS, but the other part was most definitely age.
Since most PGs are athletes, the fitting in socially is less of an issue. However, from my own experience (at least at a larger school), friend groups shifted a lot by senior year - kids matured, grew more confident, outgrew adolescent bodies, etc. With a lot more inter-class friendships, new faces that happened to be PGs were not ignored or excluded at all.
In terms of whether it helps with colleges, that depends a bit on what people are hoping for. If a PG came from a large public HS wo a lot of individualized college counseling, that alone can make a difference. If he had far better grades as a senior and then does well fall of PG year, that matters. If he’s able to take more advanced classes as a PG - that greater rigor can help, not just w admissions but with success in college. And finally more opportunities to participate in community service, arts, theater, clubs, etc. can better round out a college application.
The most important factor is student buy-in. If he doesn’t want to do this or sees it as a punishment rather than an opportunity, it won’t be beneficial.