When he gets to his unit he should go and speak with the PT staff and find out who runs the unit, or regimental football team. Tell them he is interested and take it from there. Once in the door go and make noises about wanting to try out for the army team, and/or go to the local civvy team and see if they are interested in him.
A couple of the blokes who were posted to my unit were Corps rugby players, when I say unit there were less than ten of us including the officer and sergeant major. These two blokes were posted in as we were a convenient location to put them to allow them to more or less be professional rugby players. Not only were they Corps rugby players but one of them had been picked up by London Irish and the other one was on his way to being picked up by a London club.
Neither of the two characters were what you would call academically gifted. In the normal course of things they would probably have been career Corporals, but being more, or less professional athletes helped move their careers onwards, and upwards to heights they might not have ordinarily reached in a much faster time-frame.
So, bottomline: As a sportsman your lad should do well if he can join the dots and make the connections.
