I thoroughly agree there. If I were in that father's situation, I do not know how I would handle the emotional devastation; unfortunately for him, the law as it written, does jack-shit to protect him on an insanity defense. IMO, the insanity defense requirements are not written to protect those who have acted violently in response to extreme emotional distress, nor to assist those with genuine chronic conditions, but instead to punish those who have been caught red-handed and may want to resort, falsely, to such defense. The effectiveness record of the defense is abysmal, largely, I think, because the public demand for retribution of crimes committed is far greater than the desire for rehabilitation, even in the case of people who genuinely need psychiatric help. I think the insanity defense is a trap and that is why the requirements are so whack. If the defense did what it is purported to do, the father would have a chance in hell here; he doesn't.
I don't agree with what the father did, though I understand it all too well.