This is of course tragic, possibly avoidable, well definitely avoidable, part of hunting instruction and firearms is know your target and what is behind, I have hunted in fog and it is different, but the 1st rule applies, if your not 100% sure, don't take the shot, as far as age, I think 5 might be a good idea, like Kid I started alone when I was 12, but supervised at 10. I got into trouble at 10, my 1st squirrel hunt, and a friend of my dad loaned me a browning .22 take down auto, with scope. How cool, well I was by myself, but adults were close, and walking the woods when a squirrel ran down a barbwire fence and I opened up on him, missed him but I was on a hill shooting down, later my dads boss, asked " who was shooting from the top of the hill ? " well it was me, and I was shooting towards him and his son. NO one had taught me that lesson yet, never forgot it though. Lucky!!! I do think starting kids off on a single shot is a good idea, except for centerfires and shotguns, some are so light they will beat you to death, in a 7mm or 20guage and up. Not that single shot firearms are not heavy enough by the right manufacturer, just the H&R, and those like it, not a bad firearm, but light enough on a small frame, to make you want to quit. After shooting my H&R 20 guage single shot with no butt pad, I was scared to death to shoot dad's auto 5, in 12. Nothing could be further from the truth, after my dad shot my 20 he said , GD, no wonder you don't like it.
The truth at the end, regardless of sentence ( if any ) this boy will carry this weight for as long as he lives, I wonder if he will ever hunt again. Maybe even just shoot again.
Public land is a problem, when multiple users with different purposes are allowed at the same time, hikers and hunters, at the same time, especially if the hikers or campers don't know, that hunting is going on. I think on public land, during hunting season, hunters, hikers, and campers alike should wear the minumum 200 square inches of blaze orange, and the Blaze orange hat, like they do in CO. I hunted public land there in the San Juan National forest, a mountain, and was amazed at how big the country is, and how well the blaze orange stood out when the morning light was just coming in.