Legal Question in Real Estate Law in California

My first problem with your question is that you may not have any legal right to give anyone any notices. What makes you think so? The unit doesn't seem to be yours at the moment, nor do you seem, on limited information given, to have any power whatsoever over this property.

This is not to say you couldn't obtain some control or management powers by asking a court to grant it to you. However, on the basis on information given, I'd say that when your stepfather died, your mother most likely inherited everything, especially if there were no will or trust.

That being the case, and notwithstanding that you say your mother has "mid stage dementia," she has full legal power and responsibility for her inheritance until a court of competent jurisdiction finds and declares otherwise.

If there is a tenant-related emergency (which a one-month tardiness in payment of rent does not necessarily establish), you need to get a lawyer who does conservatorships (or elder law in general) and ask a court to give you the necessary powers.

Otherwise, I think you are legally a stranger to your mother's affairs, and lack any legal or other power to involve yourself.

You have a complicated problem. You need to get some legal advice from a retained attorney. Since your zip code shows you are in Pleasant Hill, I suggest that you contact the Contra Costa County Bar Association Lawyers Referral and Information Service ("LRIS"). They have a program in which you can meet with an attorney for 1/2 hour for a nominal fee to scope out the problem. Their phone number is (925)686-6900.

Good luck. These family problems are never easy.