Francis,
It is not a conversation, it is a way of telling those closest to you about a huge milestone or achievement in your son's life. Do you want to share this great news with 10-15 deserving people or blast this on social media to a bunch of people that will look at the post for 1-2 seconds and then move onto see stupid cat tricks?
My two cents....Read what RJM is saying, then read it again. After he verbals and confirms with the head coach , If there is anything to be said at this stage, it should be a personal (no social media yet) "big thank you" directed to family, coaches, teachers, trainers, possibly members on this board that helped him in his journey and get this opportunity. In my oldest son's case it was a very long list of thank yous, and it kept him busy for a while. After he shared his news with friends, family and supporters, he called (no email, no text) a handful of other offering coaches to tell him of his decision. All coaches wished him well and only one had an attitude
Once he signs the NLI or gets an admission letter then go crazy with your social media. My oldest son's high school administration was so excited for him, they hosted a "signing day" with the local newspaper just for him. The ironic part is the Ivy League doesn't require an NLI (no athletic scholarships) so he was signing a blank piece of paper. We did this signing event after we received the admissions letter.
JMO. Best of luck to your son and family!