Is this a revolver? I figured it was a semi auto. If it’s a revolver then I can see that position although his fingers on his left hand might get a shot of hot gas from the cylinder leakage. Seen some ugly pics of left hand damaged in just that way.
Second look, it’s his thumb that might get a little hot.
What TB said. A semi-auto, probably built on a 1911 frame. The danger of the high hold is having the slide run over your hand, but the guy looks like he knows what he’s doing.
I use the thumb-by-thumb hold for revolvers too, but you never let the left thumb get very far forward, because of the danger of cylinder gap gases, like you warned. The left hand should be pressed against the right hand and the front of the grip, not wandering somewhere on the frame of the gun.