Sounds like these people sold their houses without any intention of ever leaving, so it seems like fraud in the inducement to me. As the article states, there is no landlord/tenant relationship, so ... even though I realize this is the moronic Kommune of Kalifornia ... a court should easily reach the conclusion, at a minimum, of:
1. The "seller" does NOT have to leave the property.
2. The "seller" never actually intended to relinquish his property; therefore, the "sales" proceeds should be immediately returned to the "buyer" because a sale never happened.
3. The "seller" also owes the "buyer" a market-rate of interest during the time he held the "sales" proceeds and should immediately pay that to the "buyer."
4. The "seller" should immediately pay all court costs.
But, of course, this would only happen where the state and local government respects the rule of law. I feel badly for this young couple, but this is what you get when you vote to keep Democrats in power.