Not only that but if it takes you 5 minutes of driving to realize u don’t have brakes it’s time you turn in your licence. I have burst lines before and once a line fails you no longer have any pedal pressure. If the line was cut when he got in his car right when starting the vehicle he should have stopped as the pedal went to the floor. More than likely his shit was rotted as I don’t see a pic of this cut line, if it were cut it would be incredibly obvious vs corrosion.