If you are low tech style and keep a copy of your keys written down then write a letter to your loved ones with step by step instructions and keys, and keep it in the same place. No greater risk that you are already taking. Of course if the place will not be found when you die, thats a problem ;-)

A more flexible approach could be to give them the password to an encrypted drive which will be found when you die. This has instructions/keys but you dont need to tell them that its BTC related now if you dont want to. They have to steal the drive to rob you of the coins....and if thats a consideration then why leave them anything! Help the BTC community with a little extra price inflation!

I also wouldnt be surprised if some of the secure BTC storage providers like Xapo or the like have a related service? If you have registered the account with ID etc then it should transfer to the heir and you can leave instructions in the will without mentioning too many details or keys etc? Just say I have an account with xxxx and all funds pass to xxxxx?