It depends where you store them. You can store your coins on an online exchange, in a wallet or as a code on a piece of paper. So if you die then whoever you told your passwords to for the online wallet wil get your coins. Oh hold on you didn't tell anyone the passwords? Well then they will stay there possibly forever. If your family knows about them but not the passwords I would imagine they could go through a very long process to regain access involving showing death certificate etc. But that's only if you gave real name and they can trace the ISP/PC you used to log in to the wallet to deposit the coins.

You can see where this is going - make a back up of your passwords and let your next of kin know where the passwords are.