Now let me respond to your brakes question.
The RV in your case or the truck in mine is designed to stop the fully loaded RV or truck ONLY. In my case, the truck is designed to stop 11,500 lbs of loaded truck, and NOT the extra 14,000 lbs of FW I am towing. Will the truck stop the entire rig if the camper brakes are not working? Yes, but it will take longer and you will go farther before you stop. Although not as dramatic, the same is true of a 20,000 lb RV and a 4,000 lb toad (and 500 lb dolly). That is why trailer brakes are required in most states.
Trailers and FW have drum brakes with electric actuators in each wheel assembly. When I step on the truck brakes, a built in trailer brake controller knows it and sends an electric signal to the FW to apply the brakes. There is also a lever so I can apply the trailer brakes independently if needed. That brake stops the trailer and the truck brakes stop the truck, or something like that!
RVs with a toad usually use some form of surge brakes. Basic systems have a receiver tube within a receiver tube. The outside tube is firmly attached to the RV. The inside tube to the toad. When the RV accelerates, the inner tube moves backward (within limits!) and pulls the toad. When the RV slows down, the inner tube slides forward, activating a lever which applies the brakes on the toad or dolly. Ready Brake has a simple video of this process. When the RV slows, a cable apples pressure to the car brake pedal to slow or stop the car.
Some toad brake systems have an inertia switch which recognizes this slowing down and converts it to electrical / mechanical actions to press the toad brake pedal.
Acceleration or stopping releases the brake in both systems.
Hopefully, this helps you.