You can authorize 5 computers/Devices to a song/application - doing it legally.
So get him to sign into your account and find the game in the application store, click it and becareful, it SHOULD say "YOU HAVE ALREADY PURCHASED..... i think(from memory)" then just download it, if this all works, then go to the application library, double click the game and log in again.
Then just send it to the phone.
BUT! - It may not say you have already purchased the game, but i have worked a way to work around this and.... other things