To properly answer the question put forth, his father could just as easily caught the flu from visitors to the hospital rather than Hospital staff. Influenza virus survives for many hours on surfaces people touch. Its also possible the father caught the flu virus prior to even getting to the hospital since their is an incubation period of 1 to 4 days before symptoms appear.

Fact, flu vaccines are often mismatched, meaning they don't match the strains going around, so no real or imagined protection occurs. Influenza infection rates rarely change from one season to the next. Only 1/3rd of the population gets a flu shot. Add up the facts and you realize flu vaccines play no real roll in protecting people from influenza.