The conundrum is how to pass your bitcoin private keys to your heir (who may be too young to understand security) without using a third party which is a serious security breach.
There is a new, hardware wallet solution (like a super Trezor) called Keevo which provides four-factor authentication. It claims to have solved the conundrum once and for all. It uses fingerprints, smart-will technology, paperless storage, and multi-factor/multi-sig authentication amongst many other features to make it a true next-generation service.
Keevo supports the major cryptocurrencies like ETH, Dash, LTC, XLM and many more.
Cryptodaily