We don't know, but people have been speculating that the death was faked in order to get away with theft and mismanagement of Quadriga wallets. Every new detail seems to suggest a scam and fake death.
The scam conclusion is stronger than, and does not rely on, the fake death one. The combination does seem to be the most likely, but even if he's really dead, this still looks like a scam.
The odds of it not being a scam is pretty tiny number. Not scientific notation small, but getting there.