I remember a presentation at DEFCON some years ago on this topic. Most of the state death registration systems had virtually no security or verification at the time. It's probably a stretch to describe this as "hacking" when it was probably more akin to fraudulently filling out a couple of forms.

Probably would have gotten away with it if he didn't start selling it as a service

Looks like he in fact succeeded in avoiding the payments? Like the meme, the task failed successfully. Not sure what happens when he gets out of prison.