It probably was mandatory. He probably did receive the flu shot. And if he did, it did him absolutely no good whatsoever.
If you really need an exact answer, go get a psychic and see if you can drum the kid up from the dead.
You don't think the father of the kid would know? The one who was the source of this anecdotal evidence?
So send him a PM. It sounds like you are one of those folks that think science is a conspiracy. And you would never trust the big pharma companies.
Personally, I think that way of looking at the world is ridiculous. Its like thinking the world is flat because you cannot see the curve.
I prefer not to get small pox, so I am glad my school system believed in science in 1965.