Legal Question in Landlord & Tenant Law in California

The judge was probably wrong. The banning of attorneys from small claims court is done to prevent attorneys-at-law from turning an informal process into one filled with legal technicalities and where claimants would have to hire attorneys to represent themselves even though the legal fees charged might exceed the value of the case. You are an attorney-in-fact,not at-law.

If your mother has the power to appoint successor administrators she should do that [she also does not need the added burden of being an administrator while so sick], although court approval might be necessary. You could file a civil limited jurisdiction case for both the UD and the rent owed and try to push the case along quickly. You could try to buy the tenants if they are judgment proof by offering them some money to move.

As you and I know, Mr. Shers' answer is useless because you were not in small claims court and therefore that had nothing to do with your problem. In the circumstances you describe there are several possible reasons the court found your mother's absence to be a fatal defect in your case. And, of course, it did not help matters that courts are notoriously pro-tenant in UD cases.

As for what you can and should do, unfortunately you do not provide enough information about exactly what your mother's status as "administrator" of the property is. Realistically, it probably is sufficiently complicated legally, and dependent on documents, that you could never really post all the necessary information here for us to answer. So, bottom line, you are going to have to bite the bullet and pay an attorney to help you straighten this out.