Cabbage Dad wrote: Would it make sense for your son to have a direct conversation with the RC expressing interest but remaining concerns that HC doesn't seem to have much interest in him?
That email the HC sent could actually prove to be a great measuring stick for this particular school as to exactly where your son needs to be in order to be wanted. It is a great focal point for productive specific dialog. Then, as bacdor alluded, you can avoid the spend and time if the strength of interest isn't reciprocated by the decision-maker.
This.