Thanks, all. He's a linebacker, so not throwing a football.
I've told him every year, it won't hurt my feelings one bit if you quit football, but he likes to play, so I stay out of it. His baseball coach is the linebacker coach, so I think he keeps an eye on Son and makes sure his strength training is good for a combo football/baseball player. I've asked Son to talk to him about this topic, too, so maybe he'll advise him on what to do outside of football to be prepared for the camp and the showcase. But it sounds as if you all suggest that a couple times a week throwing/fielding/swinging, with a bit more the week before the event is probably the best he can do.
Pitchingfan, your story hits home. We will have a 5 hour drive after a football game to the showcase venue. Not ideal situation, but I don't think they will move the showcase for us!