If cheaters were caught with conclusive evidence, they simply should be banned for all time in this game.
They didn't cheat by accident ("oops, my mum installed a cheat in my e+ folder while I was at school") but on pure purpose and will continue to do this even if they whine about it.

Cheaters are just disliked mostly by honest gamers (and please don't tell me cheaters don't know this which could be seen as a sign of innocence), they disturb the whole gaming thing. As said, if they were not caught, they would continue.

There are many games people like. So let him play another game and he can choose to play with or without cheats in the future, else he probably won't find a lesson in this.