Writing a will should be the first step, because we want to make sure that the right people inherit our money. Without a will the law will determine who inherits and this could also lead to lawsuits within the family. In this will you should definitely write down that there are crypto currencies part of your financial assets and your family needs to access them separately. Instead of putting any private keys into the will you could rent a deposit box at the local bank and store all important documents there. Like that your relatives will find everything in one place and should have no problem claiming your crypto portfolio. Depending on the size of your crypto portfolio the fee for renting a deposit box are quite small in comparison or maybe you already have one for other things. For example, holding some commodities like silver or gold, or family jewelry and watches I would preferably keep at the bank. There they are insured and you don't have to worry about thieves when going on vacation.