Looks like that barrel metal is quite thin. Looks like it would not contain an over pressure load, whatever that load may be. My dumbass brother (50 years ago, he's smarter now!

double charged a shell while reloading for ducks. He loaded 30-31 grains of red dot powder and 1 3/8 oz. shot on the old MEC.. (wrong bar) He was supposed to change the MEC bottle to Herco powder. Dad had bought a new Mossberg 500 pump shotgun, about 1968, and that was the shotgun he used about a year later....or rather destroyed. Right handed shooter and when he pulled the trigger it kicked hard and he said it looked like a flame thrower. Then he felt a "sting" in his left hand but no damage to him. (missed the pheasant too) The internals of the action/bolt everything fell out the bottom to the ground. Dad sent it to Mossberg with a note of what happened, and the amount of powder used, shot etc.. Ask them to repair it. They send a NEW shotgun back, no charge, with a note they felt their shotgun should have withstood the pressure. Evidently, some shotgun barrel steel is thick enough to withstand 2-3 times ordinary pressures. Lighter expensive trap guns, maybe not so much? I know my brother and I got an abrupt talking to (another ass chewing..Ha Ha) from my less than friendly German ancestry father. I got chewed out, and had nothing to do with my older brother's dumb mistake. Back then, and in those teenage years, when the sh!!t hit the fan, it was best to vanish for a few hours. Oh the fun....
Hope this guy finds a really good surgeon. Going to be life changing....Seems Lifes distribution of "short straws" is wildly capricious.