If it’s just an isolated non displaced rib fracture, they probably set him up on NSAIDs and sent him home after a few hours. For these injuries treatment is usually pretty conservative. Most completely heal within 6 weeks. If it was displaced, if he was older, or if there were multiple fractures, then things get more complicated.
Returning to sports is completely dependent on him and his pain. Usually within 3 weeks, but could be as early as 1 week if he’s feeling good and can wear some extra protection over the area.