Congrats to your son, and best of luck.
I'm going to err on the side that coach is unable to respond yet. Most coaches/teachers/educators do this for a living because they want to help young people. Give it some time. I know many educators, and they seem to pick some crazy vacations and trips. I could never do what they do from August to June. I know two educators on the Appalachian Trail at this very moment, and a couple others that won grants to study abroad in another hemisphere. Give it another week, and then try to call them (no email or text). Leave a message if they don't answer. Good luck.