KUDOs to the Cato CFI for trying to prevent the flight - it takes balls to stand up like that in the interests of safety. Sadly it ended tragically.
As Rude Boy points out, it is attitude and often not poor ability that creates a dangerous pilot. In my instructing days I noticed that the overconfident pilots tended to feature more prominently in the accident statistics. The slow learners often make the safe pilots, since they are more often than not aware of their limitations.