I don't use that phrase often; I hear people say it, "There's a special place in hell for people like that"...
Its very tempting in this case.
But what disturbs me more is that this didn't happen in a vacuum. This house was not situated on 10 acres in the middle of the mountains. It was in a neighborhood. Mail got delivered. Meters got read. People saw, smelled, and suspected, but nothing happened until things were irrevocably bad. This lady died on 25 October and the assault on her dignity doesn't rest solely with her grandson.
If you see things, suspect things, say something.