You want your cheek on the buttstock when you shoot because it gives you a more consistent sight picture. The rifle kicks backwards, not upwards. You don't want your eyes near the optics because of that backwards movement. That can get you a black eye if you're too close.

His shooting stance looks fine except for his chicken wing sticking out. Tuck that in or get it shot off.

5.56mm is notorious for its monstrous recoil, so you have a valid point.