2018SSDAD,
What discussions with coaches did your son have at HF?
Coaches are pretty accessible at HF, even with the large # of athletes. I recommend to HF attendees to have a gameplan going into the event. The majority of coaches/colleges are published in advance. A student-athlete should make contact in advance of HF..."coach, I'm going to be at HF Session #X and look forward to seeing you there". And they should make personal contact with (i.e., talk to face to face) the coaches/colleges on his vetted list at HF. The event is set up for this. And that's one way that pitchers and non-pitchers will get attention...by expressing interest in the colleges on the player's vetted list in person and often.
From those discussions, some next steps will naturally come out. If they did, follow up on those now.
Regardless, I agree with Duck...reach out now to follow up with every school on his vetted list. Particularly for a 2018, and IMHO, it doesn't matter the level of the program. Summer 2017 is the prime recruiting time for high academic 2018's.
Good luck!