No pilot I know would pull full up at altitude because of loss of airspeed. We fly pitch and power for altitude and weight. Never would we pull up in a steep climb at that altitude. We have a checklist for that. Too bad the captain went back for rest when it happened. He could have handled it properly in my opinion. I only did one of those long flights to Sao Paulo and back and I didn't like leaving the cockpit to two FO's even though I trusted them. I never did it again. All of our junior FO's had at least 3 times the experience of the PF in Air France. Probably 100 times more hands on no autopilot flying.