Perhaps for your friend competitive stress has diminished. When I first started shooting PPC (police pistol combat) I was so nervous that it would trigger terrible stomach aches and the desire to poop just before the match. I would prepare early so that I could run up to the clubhouse for relief. Nowadays I get a bit shaky but not as bad as in the beginning. IPSC and Threegun and even bowling shoots never got easier on my gut. So in some competitive endeavors and perhaps for some folks competition might not induce high stress. For me it certainly does.
Quick story........I was preparing mentally for a stage in three gun that required only shotgun and pistol. I was mapping my reload areas mentally so as to most efficiently reload my shotty. Finally I had it all figured out. My turn came up and I played everything once more in my head. The buzzer went off and my mind went blank. I ended up running my shotty dry. I fell apart completely although my score was still good it wasn't near what it should have been. Pure pressure.