I showed my paper wallets to my girlfriend once and told her how much they are worth, but she just asked me, if I would put that money into a bank.
I couldn't really bring my self to telling her, what to do, with them in case of my death, since she already worries enough about the future.
Keeping cold wallet with other important papers is useless if it's encrypted. And if it's not, it's very risky (burglars etc).
There are always some traditional ways like notary or bank deposit box. But I wonder if it's possible to create some sort of decentralised contract, ie that sends specific email to the relevant person, when there's no activity on particular address for 6 months or year...
Anyway, thanks for bringing up this subject, it's worth discussion. I reckon that in 20-30 years there will be quite significant amount of bitcoins lost because of deaths, unless there are some easy solutions available.
One is possible, but get two right is not that easy.