Kyle31, welcome to the site!
What does your son's coaching staff say about him being on track to go D1? From what you've described, it sounds to me like he's at a transition point. He could continue to be big and slow, or he could develop into big and athletic. I've seen kids his age go in both directions. If he wants to be a D1 position player, being slow is going to severely limit his options. That's going to matter much less if he pitches, but he'll still need to get much stronger to get that velo up to D1 standards.
Sounds like you have him on a good team that is hitting the right tournaments. IMO, showcasing this year is not a smart use of your baseball funds. (A personal trainer would be more beneficial.) No one will care about his 14 year-old PG profile numbers if they see him hitting bombs or throwing 88 at the WWBA this summer.
Good luck and please continue to visit and learn from the many knowledgeable contributors on this forum.