We're all assuming he went peacefully in his sleep because there is nothing else to go on. But he could have had months of agony from something hideous and wasn't able to summon help. I really hope he did just go to sleep and not wake up one night.
I'm astounded that they can just board up a property without having to actually go in to assess it. Obviously because there may be someone dead inside, but what if someone was squatting inside and you board them in.
There was a case of a woman who died in her flat in London and nobody checked it for 2 years. The neighbours reported it repeatedly and the police attended but never went in. So sad that people can be so alone.