https://www.bbc.com/news/technology-47454528

Do they even has his body? And if they have a body I'd say it is about time to do a DNA check on the corpse.

I am not knowledgeable enough about these things...
Does not ownership and source of the money clearly documented in the block-chain? Theoretically to gain access to the money they have to put it one electronic step back in a block-chain. May be to the previous owners of the funds who have still access to their accounts.