In California, "Bob" was living rent-free for years in exchange for caretaking and minor repairs. There wasn't any written contract.
Six weeks ago, Bob's sister "Sue" began to spend substantial time at the residence during Bob's terminal illness. Now Bob has died, what statute or cases support Sue's claim to have rights as a tenant or squatter? What if Sue is the heir? Does Bob's tenant right pass with the estate possibly?
Neither Bob nor Sue are squatters: Bob was there with the owner's permission and Sue was there with Bob's. Adverse possession requires possession that is, well, adverse: against the wishes of the true owner.
Bob was almost certainly a tenant, paying rent in services rather than cash. Clearly, the terms of that tenancy are unclear and may not be legal but that is more likely to rebound against the landlord rather than the tenant. So long as the rent (whatever it is) continues to be paid the estate’s tenancy should continue. However, the landlord could start procedures to end the tenancy (probably requiring 1 months notice) at any time.
The facts of Bob providing consideration (caretaking and minor repairs) and receiving lodging imply a rental relationship. This apparent relationship can be the basis of protections such as against eviction. I'm not aware of anything allowing eviction protections to be inherited, as they are a protection for the person of the tenant. Eviction protection is different from leasing rights; a person may still be able to fight an eviction even if their lease has terminated.
In the absence of an explicit rental agreement, it will almost certainly be taken to be a month-to-month lease. "In California, if the tenant was on a month-to-month the tenancy terminates 30 days after their death." https://www.fastevictionservice.com/blog/dealing-with-death-of-tenant-california-laws So from that, it appears that even if Sue is not found to be a tenant, she would be able to retain tenancy for 30 days. If she is found to be a tenant, then the land owner would have to give her 30 days notice before terminating the tenancy, and Sue could, if she wish, require the owner to go through eviction proceedings.
Whether Sue was a tenant would depend on issues that your question is unclear on, such as to whether she stayed overnight and if so how often, and if the owner was aware of her presence. If she is found to have been a tenant for the six weeks, then as that is more than 30 days, she would be considered a long term tenant, giving her significant tenant rights.
