If you registered the game via impulse (which makes sense considering he's posting on the demigod msg board, but maybe not), then yes - he should be able to download the game via impulse.
At any rate, this doesn't sound like an issue with the DVD in any way... sounds like a hardware issue (or possibly software).
Anyway, if you don't have impulse, install it (www.impulsedriven.com). Then register demigod if you have not. Then download. Then choose to archive if you like and you shouldn't have to download it again.