He did, but not alone. His brother or brother-in-law, or some other adult was with his son, as was another boy. If he had left his juvenile son on the plane alone, by all means, add a reckless endangerment or some other such crime. Personally, I dont think jail time is appropriote, but neither is $1000 fine quite enough. I think something in the $5k-$10k range is much more appropriote.
IIRC, he left his son with an adult family member. What's stupid is he thought his camera would be where he left it. He should have taken his medicine and chanced it with lost and found when he got back.