Tell your friend that shoulder surgery and shooting weak hand isn't such a bad thing. I had right side surgery in November, left side in July, had each arm in a sling for 6 weeks, learned to shoot single hand during that time, first with the right, then with the left. I had never learned to shoot well left handed before the surgery, now I can shoot slow groups equally well either hand, out to 25 yards. I shot 4000 rounds left handed while my right arm was in a sling.
Joe