Perhaps they should have stopped the child before he started attending the indoctrination facilities in the first place. Monsters like this are created over a period of years.
How many times did Momma pat him on the head and tell him how proud she was when he did well in his school work? Then she gets all upset when it is time to take the Final Exam.
I can’t entirely disagree - unless there was a real genetic/chemical imbalance problem that wouldn’t have prevented it no matter what his upbringing, then the family (esp. mamma) has some blame. Still, she tried to stop him. She at least partially redeemed herself by that act (assuming the testimony is true).