Just to update: Mike searched around the LA area and found a number of places that had open appointment slots. He made a reservation at the passport acceptance office in Atwood/Placentia and both he and his brother drove up, made the appointment and were through in 15 minutes.

They (the passport acceptance office) instructed both of them to complete and submit DS-11s.

On behalf of both of them, my thanks to the FlyerTalkers - especially GUWonder for inputs, advice and recommendations.

David