Hmm....that's interesting. I would think that any damage caused by the leaky water heater would have to be paid by the property owners' insurance, not your renter's insurance. My understanding is that the renter's insurance would only cover your stuff (if the heater blew up and soaked everything in *your* apartment), or if someone was injured in your apartment.
That said, to go back to the original topic, there really is no excuse for not having renter's insurance if you have anything of value (and that includes Dish boxes). I know that in my case, the discount that I received on my auto for getting my renter's from them paid for the renter's insurance except for about $0.25 per month. If your budget is THAT tight, you probably shouldn't have Dish in the first place...
I hope that he can get something worked out with Dish that works for both of them. I don't, however, think that Dish was at fault. If he had leased a car, would he expect that Ford would just "let it go" if the car was totalled in the hurricane, but he didn't have insurance on it? I really don't think so. Expensive life lesson, but it could have been worse than a Dish box or two...