My son says he parked car for several days and when he started backing out of parking space he heard a clunk as the car started to move and then grinding. We talked, it sounded like brakes stuck to rotors and they had broken loose, then some rust wearing off.

Unfortunately it has happened a few more times, and he says the back left wheel area smells hot and the wheel is noticeably hotter than others.

I will have one day to see the car this week if it seems like something I can fix, otherwise he'll take it to the local indy shop.

Any idea what is going on, if it is fixable at home (I have pretty good array of tools) or otherwise what we're looking at cost-wise to have it repaired?

Any diagnostic steps he can take? Is it safe to drive at all?

Thank you for your thoughts.