This may currently be a bit beyond foolproof advice for Aunt Tilly [0] to do on her own, but:
1. Get them to use a password manager for their stuff. This can easily be a good idea all on its own, simply so that they don't reuse the same credentials everywhere.
2. The password store can be decrypted with either of two methods: A day-to-day password they memorize, or a longer key which can be stored along with the will. [1]
3. Set up the cloud services to automatically backup and share their encrypted at rest password store from their computer to various relatives and friends.
4. Take the alternate encryption key from step #1, print it on archival paper, seal it inside an opaque tamper-resistant envelope, and store the envelope along with the will--or in such a way that it reaches the right people when the person passes away.
This way they can easily keep things up-to-date with new accounts or password changes, without constantly sending new stuff to a lawyer or safe-deposit box or whatever.
_______
[0] An archetypal relative who is "not good with computers."
[1] This isn't algorithmically impossible by any means, but it's a use-case not all password managers will support. An alternative is to tell them "never change your master password ever", and then just duplicate it in the sealed envelope.
Various family members have their accounts & passwords in a binder, in a known location. Not ideal, but there's no technology involved so it is "elder proof".
Could it be left with their attorney? Not really - the attorneys don't want the paper and don't want the additional responsibility for keeping it secure. Plus having to make it available at their office for recording occasional password changes.
There's an additional threat to consider: What happens when it burns up in a fire, soaks to illegibility in a flood, etc?
More than half the reason I implore my parents to digitize their ink-scrawled Sheet Of Login Stuff involves having an off-site backup. Leveraging it to help with end-of-life planning is just a bonus.
> 2. The password store can be decrypted with either of two methods: A day-to-day password they memorize, or a longer key which can be stored along with the will.
The longer key is kind of pointless given the shorter password, unless that shorter password only works with a hardware key.
P.S.: Another bonus to this is that the sealed envelope along isn't enough for the holder to empty all of Aunt Tillie's bank accounts and flee the country. Whoever has custody of it would at least need to conspire-with or trick one of the family members into sharing them a copy of the encrypted store.
Also, for bonus disaster-preparedness: When setting up the cloud service to backup+share the encrypted file, also include the original installer for the password-safe software. It avoids the problem of trying to find code from a discontinued software project or which successor-project may or may not compatibly open the file.
1. Get them to use a password manager for their stuff. This can easily be a good idea all on its own, simply so that they don't reuse the same credentials everywhere.
2. The password store can be decrypted with either of two methods: A day-to-day password they memorize, or a longer key which can be stored along with the will. [1]
3. Set up the cloud services to automatically backup and share their encrypted at rest password store from their computer to various relatives and friends.
4. Take the alternate encryption key from step #1, print it on archival paper, seal it inside an opaque tamper-resistant envelope, and store the envelope along with the will--or in such a way that it reaches the right people when the person passes away.
This way they can easily keep things up-to-date with new accounts or password changes, without constantly sending new stuff to a lawyer or safe-deposit box or whatever.
_______
[0] An archetypal relative who is "not good with computers."
[1] This isn't algorithmically impossible by any means, but it's a use-case not all password managers will support. An alternative is to tell them "never change your master password ever", and then just duplicate it in the sealed envelope.