Shoulder Sublaxation

My son is 11 years old and dislocated his left shoulder playing football and told know one he then a month later at a wrestling tournament was caught trying to put his shoulder back in. Since then he has under gone extexsive reconstruction of his left shoulder. We took him to physical therapy for the first time yesterday and during his exam his therapist told us that he has loose joints and his right arm is sublaxating as well. I want to know what we can do to keep this from happening in the future, and if we should look into some type of brace for hisshoulder(s) because he wants to go back to playing baseball and football.