There is no "right to self-determination" - people are committed all the time to prevent them from harming themselves.
This man was violated.
Yet is also alive.
Everything else-arguing over how hot the fire was, etc-is sophistry.
The facts are not sophistry.
The question of whether he had any chance at all of saving a child or if he was just - crazed by panic and grief - rushing toward certain death is a very serious question.
What is sophistry is to discuss an urgent real-life situation in abstract Lockean terms as if the stepfather were a calm, rational actor making carefully informed decisions.
He was not.
And there is most certainly a right to self-determination. It takes a court of law to override this right, to involuntarily commit a man to protect him from himself. But the father in this case had no due process.