The other guy fucked up by telling you he's a delivery driver. More than likely his insurance doesn't know that, and will either raise his premium or drop him altogether for it. The only "favor" you can do for him is leave out the delivery driver part when you file the claim.
If the dealer finds ANYTHING wrong, which sounds like they will, they're going to want to replace it since they don't "fix" transmissions, and can easily deny warranty if they dig just a little. Hope for the best, expect the worst.