My daughter (pitcher) was diagnosed with first tendonitis of the elbow and the the sprain of the ulner collateral ligament when she was 16. She went to therapy 3 times a week however didn't take time
off. The sprain got worse ..began having numbness in her fingers as the fluid built up in her
elbow while pitching. (You could always tell as before she threw a pitch she would shake her hand and arm--) To make a long story short, she was scoped and fluid drained, followed by therapy again. Eventually she ended up having TJ. She was put on celebrex, vioxx and mobic at different times to help with the pain.
I realize guys motion etc is different. IMO her
sprain was caused by overuse, relying on and throwing the same pitch(that was almost unhittable)while playing in the cold temperatures.
Good luck to your son. Be sure to have him complete the full course of therapy and rest that arm!....there will be plenty more games in his future.