Welcome to the site!
Disclaimer... I'm a HS coach.
If he is as well connected and talented as it sounds, it most likely won't matter in his college recruiting process and any pro interest. But, as others said, it might. Still, to me, that's not a reason to decide to continue playing HS baseball. If his HS program is only one step back from his summer program, that's not that bad, really. I guess I'd have to hear just how bad. Only you and he know the specifics. Does he have his HS friends playing on the HS team? Is he putting off the "i'm too good for that" vibe or are there serious issues like complete opposite teaching with no flexibility for a great player getting solid outside instruction? Does he not recognize and appreciate the many special aspects of HS ball as compared to travel, showcase and eventually college ball? Even if the team is not good, there are an abundance of things special with HS ball that he won't get anywhere else. Obviously, it would be difficult for the coaching to measure up to what he is getting outside of HS. So what.
I've said it here several times on this same subject... playing for your school while it is still somewhat of a game and not a job, everyone pulling for the same goal without necessarily having an eye on the next level, playing for community/cross-town rivalry, learning how to really be a good teammate often in less-than-ideal conditions, becoming a team leader, helping your school program improve/gain pride and respectability, etc., etc. HS games are a great, fun environment for him to actually put all his hard work into games, even if not the competitive level of summer.
Travel is largely to be seen by colleges. College is a full time job. If he loves baseball, what is so bad about the HS program that he feels he shouldn't be part of the things I refer to? I suppose in some cases it can be that bad. Like I said, only he and you know if that is the case for him.
I'd be careful, though, about calling summer travel "the real deal". For many on the HS team, HS is the real deal and whether he speaks it or puts it off as his air, that wouldn't be good for anyone. Knowing when to show a bit of humility is yet another lesson that can be learned.