14 year old baseball pitcher

I have a 14 year old boy whom last year was diagnosed with a stress fracture in his throwing arm. He has seen 2 different ortho. doctors and both seem to think that the stress fracture was not related to throwing. We cannot think of any one instance where this could have occured other than in the previous season he dove for a ball while playing the outfield and did roll over onto his arm, still no way to know for sure. The fracture itself was located on the inside of the humerus in between the shoulder and elbow but a tad closer to the distal end. Neither growth plate was affected and were said to be in good shape. In the preceeding winter months he did participate in a weight training regiman that included light to moderate weight that he had no trouble performing 15 reps per excercise. He also did some medicine ball work that consisted of several types of overhead two handed throws into a wall. The stress fracture was diagnosed in the month of july which was after the above training regiman. At that point he stopped doing everything including bike riding,lawn mowing and of course baseball by doctors orders. After one month he was re xrayed and the stress fracture was said to be sealed and in good shape. He still did nothing until october when we started a very light tubing regiman as well as some very easy playing of catch, all was performed with no reported pain or discomfort. After the start of this new year he started a little more agressive training efforts but not quite as demanding as the previous winter. Everything seemed to be going fine than he started to feel some discomfort in his bicep area which is where he said he hurt at the time of the stress fracture. I took him back to the doctor and he was xrayed and the results were negative and his growth plates were said to be fine. At that time he was said to have some tendonitus in his supraspinatus tendon. He has since started with a physical therapist in a rehab program. In his last visit to the physical therapist upon my request he was also checked for some bicep tendonitus in which the therapist said he did have some inflamation in the bicep tendon. Obvously my first concern is his health, if he does not pitch this year that is fine with me Id rather have him be sound and able to compete at the high school level next year. I guess what Im asking is what should he be doing now? Although I do trust the physical therapist I just dont think hes taking a sports minded approach to the rehab but than again Im not the therapist. If hes in no pain as far as motion should he be doing something more than just a few tubing excercises as well as some scap stabilizing excercises? The only time he feels discomfort is when he is actually throwing and perhaps afterwards but nothing to major according to him. Thankyou!