His father dumped the mother and for periods of time defaulted on child support, while having another baby with the young replacement. The mother was blindsided, according to the shooter's screed. If the shooter's detailed diary is even 50% accurate, she also tried mightily to provide lots of friendship opportunities and worked hard to find a school that could deal with the kid's Asperger's syndrome, which is very hard to manage for mainstream schools. The dad is the one who threw his family under the bus.
That’s a fair assessment.