Hello, It is hard to say if the motor is junk without acutally running some tests on it. Overheating a car can eventually ruin the motor so it is possible. I would have had the car looked at myself before making the decision to junk the car especially if the vehicle were not mine and without talking to the owner. It does sound somewhat fishy to me also.
Hope i can find more info from junk yard tomorrow and pass info to you for some idea of replacement cost. Person is on a limited income and thought transportation was going to be a reasonable cost----wrong.