Sorry to hear for your unfortunate experience. To address your firefight and why you ran into such trouble with extinguishment. The brakes were red hot. Your first choice to knock down the fire with a dry chemical extinguisher was a correct choice. The reason you experienced several re-ignition issues was heat. The brakes needed to be cooled.
I always carry a small water extinguisher with us for cooling, along with several ABC type dry chemical extinguishers. Retired firefighter, maybe a little bit over cautious.
Since it is not practical for everyone to carry different types of extinguishers, I suggest we all carry at least two (2) of the standard ABC type extinguishers. One near the front door and one in the rear of the coach. Additionally, carry a couple gallons of bottled water to cool off what was on fire to prevent re-ignition.
When confronted with fire, immediately knock down the fire with the ABC extinguisher and then, once the flames have stopped, grab a gallon of bottled water, small bottles of water or fill a bucket/pan of water from the sink or outside shower if you have one to cool off what was on fire. This will lower the flash point of the substance that is on fire to prevent re-ignition.
Most importantly, stay calm, think clearly, and act with purpose. Have a plan. Make sure everyone has exited the vehicle and is in a safe location. Then, if you’re confident in your abilities try to knock down the fire. If not, stay in a safe spot and let it burn.
Additionally, as a reminder to everyone, please check your smoke detectors and change batteries twice a year at time change. Most detectors are located in or near the kitchen area. I love bacon, so more than once I have found the detector in a drawer since our dog hates the sound when it goes off. We have had many discussions regarding the importance of the detector returned to its location. The compromise was I do the dishes and make sure the detector is returned to its original location after a meal with something good like bacon . Win some, lose some.