Hearing what happened, his father told Jack of his ability to take in the consequences of life and death decisions. He advised Jack to avoid being a hero because he didn't have what it took to cope with failing.
It is really an odd statement by Christian to his son about a school yard fight to put it into terms of making "life and death decisions." For a few, it was a clue to a theory, like Hurley's Fall, that the story of Jack we saw in the series was not true at all.
Various threads of theories can be woven into a composite theory on this incident: that children don't directly go to heaven, they have a chance to live a new life in an alternative world view of their choosing; that Jack's fight ended one life but began a new one; that the incident and his father's words traumatized Jack into a mental state where he fantasizes that he is the man his father wanted him to be; that Jack's back story was all an illusion, a made up story in a place of make-believe; that Jack was Christian's "David" in Christian's own sideways world life.
With all the childhood struggles of the main characters, the alternative theory that they all died as children but were granted a true-to-life experience with angels without wings is an appealing concept. It throws away all the inconsistencies and continuity errors because it is fantasy. But as a fantasy, it creates its own problems, mainly the initial stated premise of the show itself.
If Christian's harsh assessment of Jack, that he could never be the hero, was the most important thing in Jack's mind, that fault could have been etched in Jack's conscious. Jack's entire life was to reach hero status - - - but one cannot call oneself a hero. It is a titled earned from recognition from other people.
On the island, did anyone really call Jack a hero? Jack lost more fights than he won. Many of Jack's decisions led to disasters such as communicating with the freighter. Jack lost more lives during his time on the island than lives he saved . . . which is not the resume of a hero.
And it is not necessarily heroic to die. Jack's last fight was with Flocke. Jack was beaten badly. It was Kate that ended it. But instead of Jack going back to Hurley, the new island guardian who could have saved his friend, Jack went to the bamboo jungle to die. For a man hellbent on survival for six seasons, this seemed wrong. His sacrifice was not meaningful nor served a purpose. It is almost self-delusional to cast oneself as the martyr in a cause that is already completely over. This tends to make Jack more important in Jack's own mind. It also tends to think of the story more coming from Jack's own mind than reality.
