Legal Question in Real Estate Law in California

Based upon limited facts given, I'd guess the property is in San Luis Obispo, which diesn't have a rent-control ordinance that might limit a landlord's right to terminate a rental, and although I don't do a lot of work with Section 8 properties, I'm doubtful that the rules regarding termination of a rental are different. That would leave, perhaps, a theory of some kind of unlawful discrimination against the tenant based upon mental illness. This also I don't give much of a chance.