Brake Disc Pads problems of the 2016 Chevrolet Suburban

While driving vehicle, the brakes suddenly became very hard to depress. This caused the driver, my father who borrowed the vehicle, to have to two-foot the brake in order to get any sort of braking to occur. While doing this, he was moving at a 25-30 mph and had to steer into a parking lot. Stopping distance increased dramatically over what would have been a normal driving condition. After some time, while trying to hobble the vehicle to a mechanic and using only back roads, the brakes began to work again with full and normal feel on the brake pedal. It should be noted too that there was a loud sound coming from the brakes at that time and that rotors, brake pads, etc. Was all in good shape as is/was still in very good working order.