she91434,
I seriously doubt a coach is "spreading his displeasure" for the NLI release. That insinuates he is going out of his way to single your son out. In my mind, it is much more plausible that these new programs have reached out to the old program for feedback, and the feedback is not positive since the school was "left at the alter". If I was one of the new coaches I would listen to the old coach but I would form my own opinions about your son's athletic abilities and his ability to commit. Another issue you may run into is available athletic scholarship money. Possibly these coaches are thinking it is going to take some money to get your son, but all of their scholarship money is spoken for in the current NLI class. Certainly something worth discussing with your son and any potential new coach.
This is a very slow time in college baseball recruiting as many coaches are waiting on official word from Admissions. keewart pointed out it is a "quiet time" which is true, but coaches have the latitude to contact your son by phone or email. So, I would give it some time and I would reach out to more programs if that is possible.
Good luck!