jsingerjj,
All my very best wishes to your son in his recovery and for you in supporting and encouraging him through the process.
It certainly can be a long recovery and rehabilitation. The process is not a straight line, either. It takes a ton of mental focus and tenacity to follow the rehab program, to not overdue it or get overly optimistic on the good days and equally to stay even on the tough days.
There is a DIII catcher who was just named a DIII All American and West Region player of the year. He had a major shoulder procedure right after HS.
During his freshman year, he mostly DH'd but returned to catching as a sophomore and got progressively better.
It may take 8-12 months for your son to heal.
This is not a time to be overly optimistic or pessimistic. Take it one day at a time. and help him focus on doing the things necessary every single day to get better and healthy hour by hour and day by day.
Try your best to help him avoid the thinking of how fast he needs to recover.