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It's my problem because my family doesn't know or doesn't even know what is bitcoin, so it's difficult to tell them at this moment I'm hoping that maybe soon because the world is getting exposure in bitcoin a lot of people maybe would be interested in bitcoin. We dont really know when we are going to die and if that happened your bitcoin is just going to be lost forever. But having a journal seems a good idea where they could read after you die where all of the details like private key password etc is in there since I already have one where are store most of my private keys. But for now, maybe I could say I don't trust them when my small investment 
.pull out the coins and able to exchange it with fiat and that should be enough.If you cant just trust them for now then dont reveal that you've been saving up some coins
and when the time comes that you die then they have the idea on how to open your wallet and of course you should tell them if you do have the chance but for more secure then
they do just give out some hint.
That's what I did for my daughter. Since she's computer literate already, I have shared the basics on how to access my holdings and what to do with it. We don't know what will future brings so it's better to be ready for the possibilities. It's better that we'll have something to leave them in case unexpected things happen.