If you have a router with say 4 ports, you can run a multiplayer game over a few computers. I often did that with my daughters before we started playing public servers.
He can also play single player survival or creative without internet.
His friends probably told him about the cracked version, but if he buys it then would get to play on many more servers whenever he gets the chance to be online.
It is a great investment as it's a game you don't get tired of quickly and there are regular content updates.