[IncRnd]

It's no different from leaving any bank account to an heir. You can leave the key to a safety deposit box that the named heir has to physically be present to claim.

You should be careful about using technical solutions, like secret sharing, since this is not a technical problem. It is a legal problem, and you don't want parties to conspire to obtain the property contrary to your wishes.

[thatha7777]

There is something ironic about trusting your decentralized cryptocurrencies to a centralized institution (like a bank that offers safety deposit boxes).

Someone who keeps enough assets in cryptocurrencies to want to include them in their will, chances are that they have a preference towards decentralized systems (or a distrurst/dislike of current authority/government-based systems). Nothing stops a government from forcing a bank to turn over the contents of a safety deposit box.

I definitely know 5 people that I can trust to not collude, even in the face of a subpoena or some government-issued directive.

[IncRnd]

Do what works best in your own personal situation, secret sharing, leave a riddle that only the specific heir can answer in order to find a location, safety deposit box, etc.

Just be aware that if you are leaving anything significant, people many times act differently when seeing dollar signs. Not just collusion, but refusing to divulge their secret without themselves getting paid.

Either way, you are trusting someone to one degree or another. If the expected passing is decades away, people losing their key material is a significant risk.