Women may on occasion be cruel to some men, but as a rule men are more cruel to women, if anyone is tallying the score.
It seems to me that this kid was extremely spoiled, and perhaps did not fit in because he was half Malaysian, loved his mother more than his father (whom he resented for marrying a Moroccan woman) and was mentally unstable due to some sort of genetic imbalance.
He should never have been permitted to own a gun.