I don’t know his parents or anything about their real situation, but one thing to bear in mind is that having a mentally ill child, especially now that it’s so hard to get treatment for him, puts a huge strain on a marriage. He was diagnosed as having some form of mental illness or problem at a very young age, and when that happens, the the life of the entire family begins to revolve around this child and there often is a lot of conflict and anger.
I would agree, if his father weren’t a horndog who posted naked pictures of his new young piece of wife online just as the kid was entering puberty, fought a big custody battle to insist that the child stay at his house during alternate weeks with the resentful, harsh stepmother even when the father traveled out of the country for the best part of three years on a fool’s errand (making an anti-Christian documentary that flopped) and failing to pay child support to the mother after said fool’s errand. The mother had to move from one cramped living space to another with two kids, and watch her husband make a complete fool out of himself having another baby even when he was never there for his mentally ill child and too broke to pay his obligations — but not too broke to live with Hollywood accessories, clothing, swimming pool, cars more expensive than a house, et cetera. That child never had a chance. Just like Adam Lanza, whose father checked out and married a younger model as soon as it dawned on him that he had a special needs kid on his hands. Scumbags.
He developed his problems after his folks divorced. More likely he had organic causality but triggered by the divorce