If you want to transfer your crypto to your relatives, then there should be no problem with that. But if you die and there is no one to transfer their bitcoins to, they should return to the market. I think so. Or go to the crypto tax account.
If we would think of it, it is actually a matter that should be handled as soon as the moderators of bitcoin can. If ever a whale or a person holding large amount of bitcoin dies, would it be detrimental for bitcoin's value as time passes by? It would be best if some of the person's relative or closest friend has a key access with all his bitcoin so that it wouldn't go to waste or be stucked on a deceased person's wallet forever. It will also be a great help for many who wants to make sure that his wealth will be beneficial for his family even when he's already gone in this world.
