Rear brakes

"if it was destroying my rotors I would feel it in the pedal or something."

Which pedal are you referring to? With the parking brake not functioning, you will not notice anything with the regular brake pedal. You could take off every part associated with the parking brakes and not notice anything unusual while driving. (This is not true for GM and Ford models with rear disc brakes, but that is a story for a different time).

If one of the parking brake cables broke, the parking brake pedal will be easy to push all the way to the floor, and it will stay there when you pull the release handle. If that pedal stays high and is hard to push, the rear cables are likely rusted tight. Never never ever try to lubricate them to free them up. No good has ever come from that. The cable is guaranteed to stick again at some point. Failing to release is one of the biggest reasons a recently-sold used car comes back on a tow truck. The only proper repair for that is to replace the rusted cable(s). The next best thing is to cut them so they can not stick applied. In many states, including mine, it is legal for a dealer to sell a used car with non-functioning parking brakes, but it has to be disclosed on the window sticker. We only do that on the older and cheaper cars, but most reputable dealers still replace them.