Hear what your saying GOV but the old man per OP "He ordered him to turn around and face him and told him to take his hands out of his pockets as he stood there. The 19 year old hesitated and then took one hand out and started to take the other hand out" AT that time he must of had a fear of something and shot. Unfortunately, the OP does not state if the BG was armed or not. BUT your are correct, be sure, be dam sure. IT WILL be a life changing event on both sides of the weapon.
I know what you are saying about the hesitation with the young guy, but he did STILL have his back turned to the old guy. Even if the boy had a gun, he would have to turn around first to fire at the old man, or make some kind of move to turn and fire. Remember, the old man had the gun pointing at the boy already. He certainly could fire before the boy made his move to "turn and fire".
My point is that because this discussion has gone on for many posts, there are several opinions on what when, where, and how about this incident. It ISN'T "cut and dry". This thing winds up in court in most cases. I don't want that for me. Juries come up with some weird results. Remember, a jury is doing "armchair quarterbacking".
They have the luxury of looking at it from a hundred different angles, with as much time as they please. The shooter didn't have that luxury. He had to make a call immediately. If he screwed up, too bad. The jury will look at it like he should have known what he is doing if he is going to have and carry a gun. Besides, what happens when an anti-gun person, or persons, are sitting on the jury.
Finally, I'm a CCW holder, and it's pretty smelly to me. Can you imagine what it would like like to a jury?
Know your local laws boys and girls. It will save you a lot of trouble. I know you can't know all of them for every instance, but this one was a "no brainer". The old guy was wrong, and got away with it. Don't count on being that lucky.
I want "cut and dry". The officer comes, surveys the situation, thanks me for apprehending a bad guy, puts the BG in the patrol car, tells me to have a nice day, AND LEAVES. No court, no hassles!