Think about it: you're 80 years old, and frail. You come home and see not one, but TWO younger a$$holes who broke in your place, and they're stealing and ransacking shyt. They see you, bum rush you and cause you physical pain; keep in mind nobody else is there to help your old ass. You manage to get your gun out, and all of a sudden these bytch-ass clowns who just violated the fukk outta you and your property, wanna try to run and escape, and possibly never get caught and pay for what they did. You're holding instant payback in your hand right then and there.
MOST people would've done the SAME thing he did in that situation - legal or not. (keep in mind, by 'in that situation' I'm including if they were his age at the time)
It's easy to sit on your ass in the comfort of a quiet room, and talk shyt about what he should have done, or what would've been the right thing to do, or what you would have done in his situation. There's nothing like actually being IN the situation, though.
That's why I doubt there's even gonna be any charges outta this. And even if he is charged, they'll fix it in a way to give him plenty of time before the actual trial/verdict. And even then, there's a good chance he'll still be found not guilty - assuming he's even still alive by then.
Gramps will be fine.
Amen