I would say open a safety box with a reputable bank in your name, best the same bank where you have your bank account. Create a folder with detailed instructions about Bitcoin and the details needed to access your Bitcoins.

So in case of your demise whoeever will inherit your stuff will likely get access to this safety box too and has all information to use the Bitcoins.

In case your "family" decides to go to war about who gets how much of your Bitcoins that will not bother you in your grave. At least your Bitcoins are not completely lost and you don"t need to tell anyone about them before your die....