Grinding left rear brake

My father in law gave us a 2001 Dodge Intrepid that had sat for six months. He said the brakes would make some noise because they had rusted, but would quiet down after they’d been driven awhile. “Don’t worry.” Sounded like an October surprise but I drove the car 1000 miles from his home to our home. The sound was bad at first, but had lessened. Until today, when going in reverse or forwards, the noise was considerably louder, and there seemed to be more resistance. Is there even a remote possibility that my father-in-law’s assurances are correct, or are we going to die (or at least pay out a lot of money for this ‘gift’?).

The grinding noise may be from rusted rotors and pads or it may be from a parking brake that hasn’t fully disengaged or a worn wheel bearing.

You’ll have to pull the wheel and drum to see.