Unfortunately there is no way to open up ways of passing your crypto-currency to your loved ones without opening up a possible attack during your life. But this is a use case that needs to be addressed.
Require that N out of X friends agree that 'the will' needs to be opened; for that to be a contract the combinations for satisfying N need to be calculated out and those sequences of decryption the master decryption key setup.
Both the master key enciphered 'will' and the multi-party unlock blobs can be stored together, that way maintenance and updating everything is on the owner of the will. Obviously one additional copy of the master key for that would be kept in a file enciphered to just the owner's key.
Or use a secret sharing scheme, similar as the article suggets, to leave keys with notaries and family members.