[GTP Dad]

I would pull the wheels and look at the brakes. It sounds like the pads have fallen off the backing plates causing the brakes to lock. The other possibility is that the calipers are sticking and will need replaced or rebuilt. Finally, you could have a problem with the ABS system but you should get a light on the dash if that is what is happening. If the pads and rotors check out and you find that the calipers are not sticking take it to a mechanic and have the ABS system checked.