Kids do stupid things. Adults have to make rapid decisions in situations like this. Was the kid responding to his fathers commands by coming to him? We'll never know. What was the kid doing out? Lots of questions left open, but that doesn't help the father as he lives with the results of his decision to act.
Part of any family training regarding firearms in the home should include repeated instructions on what to do (as a kid) when caught in a bad situation. Hands up and submissive and identify yourself when confronted, even if you aren't going to escape discipline.
This is a real "No-Win" situation...and the media and the legal system will only screw it up more and do further harm to the family.