Just a couple points, hydraulic brake fluid is hydroscopic which means it absorbs moisture. Moisture has two negative effects, the first is that it lowers the boiling point so if you overheat the brakes in heavy brake applications it can boil the fluid off and give you brake fade. Not likely to happen in a motor home but moisture could lead to a spongy pedal. The other problem with moisture in the system is that it can cause components to rust, such as the calipers.
As a rule of thumb the system should be flushed at least every other year, and every year if you’re on top of your game.
On the calipers, I would pull them off and inspect them and the pads. You can take a set of welding vice grips and compress the cylinder and see if they are frozen. If so, replace.
Frank, Columbus, Ohio
2001 Itasca Horizon Cat 3126E 330hp
24' Enclosed Car Hauler