He's had some interest from D1 schools, mainly at camps. He has one D1/P5 (HA) school that he's been to several of the camps, the coaches all know him and gravitate right towards him to chat when he shows up. It's hard to tell if that is truly interest, but it was at one of their camps where he hit his first "measured" 100mph EV line drive (right at the hitting coach's face).
Yes, I remember having a discussion about that D1/P5 HA school. What I'm about to suggest may be a tough pill to swallow for your son as it was for my son when he was going through it. My son was shy, and introverted. But when it came to baseball and recruiting my wife and I saw another side of him...mature and very assertive with college coaches.
You're saying the D1 P5/HA coaches all know him and gravitate towards him when he shows up. He's been to a few of their camps and their interest has been casual. Clearly, they've seen him play many times. Maybe its time to find out if their interest is more than casual and possibly even serious.
If this school is among his top choices, share that information with the coach, and ask for information in return. Ask about their timeline, who makes the final recruiting decision, how many catchers are they going to take in the coming years, etc.... If he gets the "canned coachspeak recruiting lecture" then he knows where he stands in their eyes. If they make their responses personal, and provide specific details & timelines then it could be more than casual interest. Getting that first serious interest school and possible offer is the hardest part of recruiting in my opinion. But once that happens, recruiting gets much easier.
Just my experience. Good luck!