Lastpass has this as a built in feature for at least their family plan. You can set another account to be an emergency access account. The owner of that account

Lastpass has this as a built in feature for at least their family plan. You can set another account to be an emergency access account. The owner of that account can initiate a request for access to your passwords. You'll get an email informing you of the request, and you have a configurable amount of time to reject it. Failure to do so will lead to them getting access to your vault. Not sure the security mechanics involved that allow for it, but it seemed like a very neat product for this very thing (and I've added requesting access to the death checklist I gave to my wife), since it means I'm not having to provide my password to anyone (or even get it out of my head and enclose it somewhere physical), but my wife can still get access to it in the event of my death (or my being incapacitated for a sufficiently long period of time that she needs it).