I agree with Sifu Ron.
IMO, it was most likely a bad reaction to the flu shot x2 (hitting bone and bending needle also never helps!).
Don't think it has anything to do with qigong.
The real question is why did he even get a flu shot in the first place? At the very least it is a waste of time and money, and at the very worst, complications and a whole new set of problems can arise.