Rob my 2015 went thru something very similar. Same type of reasoning was used, Muscles where more advanced than his Olecranon. (Tip of the elbow). First we tried the traditional method of splint, rest of 8 weeks, therapy, strength training and throwing program. Everything went well however after his third start back in the summer the same thing happened but even worse, the stress fracture he originally had was now a full fledge fracture. This time we elected for a surgical repair that included pins, screws and support wires. surgery was July 19th and he was throwing again by late Oct and has been stronger then ever since. Hopefully your sons outcome is different but I wanted to make you aware of what he went thru and especially the outcome. Send me a Dialog if you need to. Best of luck!