Surely the car has a temperature gauge Polly? They give a basic indication of any engine problems - when the gauge starts to rise then switch off immediately. Wasn't your daughter watching it Polly?
As soon as the hose went the temperature gauge would have steadily risen from mid-range to the red section and then stayed there for some time before the engine seized. Also, the engine would probably have given plenty of warnings of a problem such as steam, smells and various alarming noises. Why did your daughter ignore all the warning signs?