He turned his back to the ball but his head wasn't and his eyes were looking directly at his outstretched arm. Honestly, move that ten yards closer to the goal with a shot going on target and the exact same body movement/situation would lead us all to screaming for a penalty. Drama over nothing for me and the lesson being don't ever turn your back on the ball and stretch your arm out. Amateur defending at best.
Maybe he should be a goalkeeper then, imagine how good he would be. Turning his back and still making the save.