I guess we will just have to wait and see. Sounds like relatively good news overall.
A few things from a non expert:
Hairline fractures can heal in one month- it really doesn't matter where it is on the body, a crack in the bone s quickly.
As for rehab- how much you need depends on the severity of the damage and how much associated muscle atrophy occurs from lack of use. If he can get back quickly, that will be doubly good, because he won't need to rebuild his shoulder muscles.
Its like a knee- if it is totally immobilized for 2 months then you have to rebuild the muscles from scratch. If you have a more minor procedure without complete immobilization then the muscles don't atrophy.
As for the labrum- lets just say we should be glad he does not have to throw a slider