It's all just rumors. No one knows what happened to him. (But he did mention that he had medical issues a while ago).
On one hand, that's the most likely thing that has happened based on literal reading of his earlier posts. So it's a reasonable guess... He may be dead or incapacitated.
On the other hand, however, he made the perfect setup for a disappearance. Assuming it's all a sham: Fail to deliver and disappear for months on end in the past, get people to believe that he has health issues. Nobody will question a sudden disappearance and after months, they will all eventually resign to the probable fact that he passed away.
So there's the looming possibility that he gave up on the game. His last message was that he could have sworn he uploaded an update.
In the past, his disappearance didn't lead to immediate loss of patrons, so he would have known his Patreon income was safe for at least a few months. 2 years and 7 months after the last game update and 2 years and 4 months since his last post, he still has 135 paying patrons on Patreon and who knows how many on Subscribestar.
He could have assumed a different identity and could be working on a different game. He could just get on with his life.
Remember that when Palmer died, his collaborators wanted to continue working on their games (they had all the assets and shared access to the account) and they notified Patreon of Palmer's passing and asked if they can continue using the same account, even if all patrons were automatically unsubscribed and would have to re-subscribe. Patreon didn't even enter into discussions but immediately disabled and erased the account.
So there are four possibilites:
- Nefastus is dead, his family notified Patreon, but for some reason they made an exception and haven't locked his account.
- Nefastus is dead, but his family has no idea of his Patreon side income which is collecting in some account unavailable to them.
- Nefastus is dead, his family is aware of the Patreon account, is taking the money and is lying that Nefastus isn't dead.
- Nefastus is dead, but he formally bequeathed the account in his will, maybe even did it before passing, so the account can't be legally locked by Patreon.
- Nefastus isn't dead, he confirmed it many times with Patreon, he's just inactive, but that in and of itself is not grounds for suspending, locking, disabling or erasing an account.
In either case, the only potentially positive outcome is that Nefastus is alive, is making updates in the background, and will make a sudden return, upload the belated update, then another one in quick succession and then continue his usual trimonthly cadence. But I wouldn't hold my breath.