Some of these kids would not be doing these things with proper parenting. Some probably are beyond that.
I agree. We don't have any way of knowing whether the boy is psychotic or has just been allowed to get away with everything all his life.
It's also possible, as his mother claims, that he was bullied. I, myself, the dullest and most compliant of people (according to my kids), have wished I could vivisect various fellow students and consign them to eternal torment. However, violently attacking a teacher (if the school's report is accurate) is something else.