Tough situation & decisions for a young man. I agree with Joe87 that your son is checking in with you to see how much latitude he has. As an FYI, very few college players like their HC for one reason or another just as most people don't like their bosses. It sounds like this guy is going out of his way to make some point with your son....I don't know what that point is and I'm guessing your son is going to be apprehensive about approaching this coach to discuss it. But, I think that is what he has to do before making any big decisions such as leaving a school he loves, or dropping the sport he loves. Requesting a one on one meeting with the HC at the end of the season would be a good starting point to get all the information he needs to make an informed decision (if any).
As always, JMO.