Just for that situation, or in the event of my death (turn 70 in less than 2 weeks), all of the cloud accounts and the Hubitat hub, etc, are registered in the house’s name, not mine, not my personal email, and I’ve got an updated file documenting the setup, DHCP lease reservations, etc.
I’ve also been fortunate enough to locate a very knowledgeable Hubitat user in our city, and I’ve put his contact info (with his permission) in that file so that she could contact him if I die, to help her with the transfer to new buyer.