That's terrible when it happens, but if you are the owner, plan ahead and share keys or recovery seeds with a trusted one or include them in your will, so that Bitcoin can be inherited and accessed by heirs.
I have read about a similar situation where a guy invested in Bitcoin, and before he died, he managed to secure a vault that only his family could access. When he passed away, his family opened the vault and found a videotape that explained how to access the Bitcoin. I think it's similar to that.
But no one thinks about this for the future because we know that none of us is ready to die.
All of us are busy in accumulating Bitcoin but most of us are not addressing this aspect of Bitcoin which is to handover the seed along with other details to our next of kin. Death is harsh reality of life which is certain while life is not. It must be clear to all of us that our Bitcoins will be lost forever in case we die and have not handed over material to our next of kin about how to access Bitcoins.
There was a similar post like that in the past and after going through that I have passed necessary details to to my family on how to access Bitcoins in case I am not with them anymore.