This is a DQ condition because he had, I’m assuming, shoulder instability.
Make sure he pays close attention to the rehab protocol. I know he’s going to want to accelerate things by doing more reps, heavier weights, etc as he undergoes physical therapy. Doing so risks the shoulder not healing right.
Since surgery was in December 17, he should be good to go by October - December 18 and be ready to commission by May 19.
As someone mentioned earlier, the remedials provided to dodmerb will be important.