My wife and I share a KeePass database for all of our credentials, including the keys to our digital kingdom. I document our LAN design, server setup, and general maintenance notes, which are synced between all of our devices via SyncThing.
I add notes and quick instructions to the important credentials, like “See Proxmox.md to start this service”, or “This password decrypts our file server drive…to do this, open a terminal and paste the following…”
She is comfortable pasting commands into a terminal already, so if anything ever happens to me I am confident she or my son will at least be able to access our data and move it to a more user-friendly format.