Is he qualified DoDMERB for NROTC or for Academy... sometimes the ROTC qualification comes later if you are already qualified for DoDMERB.
My older son received AROTC 2 years ago during 1st round and admitted to his school in September of his Senior Year. It seems like it took forever to get everything figured out! After signing letter of intent, I think it was spring time that everything was settled. He received an official letter from the PMS at school and that helped me calm down..."OK, everybody now knows he's coming!"
It will feel like a lifetime, but don't worry it will all happen. Having your son send an email off to the scholarship officer at the school's NROTC unit asking them what the steps are in the process is totally understandable. They don't want anything to happen to keep your son from joining them!! Also, go ahead and set up a phone appt with them for yourself. They know that the parents are oncerned and have questions.