Sounds as if your son has a both a good arm and some quickness! Thanks for sharing a little bit about him.
Here are questions that I might ask:
1) Do you have a recommendation for a summer team whose coach will let him play multiple positions?
2) Does this summer team coach keep careful pitch counts/refuse to overuse young players' arms? Is the coach aware of arm care programs?
3) What do you think about my son's mechanics? Do you notice any red flags regarding his throwing motion in terms of his future arm health?
4) What do you think of his lower body strength?
5) How is his mobility? Does he move well?
If this evaluator is also going to sell you on pitching lessons, I might have a lot more questions.
Sometimes, former players (depending on when they played) might not have a contemporary view of mechanics, pitch count, and arm care. That's not necessarily wrong, but if their philosophy is just "pitch more and never change your motion even though you are 13 years old" -- that can become a problem. My son at that age was in tears when his arm was hurting and his "pitching coach" said "Look, this is working for you. Just throw through it. It is too late to change your motion. You are too old." He was 14. The coach just wanted to win the summer league. We listened to the pediatrician/orthopod and shut him down. He switched to football, had a blast as the kicker, and still played HS baseball the next season (without that summer coach in his ear). I guess my point is just to be cautious.
Please write back and let us know.