I think Vaultwarden is the right place to store secrets and SSH keys. They can use the emergency recovery feature to request access after a certain period.

You could then share the complete instructions via email using a dead man's switch, which would make it easier for them to navigate those difficult times.

If you want to give that a try, I can answer any questions you have during setup and extend the free trial (the default is 14 days) until you are sure that this is the right solution.

Send us a message if we can help!