Instead, I'd wonder about another possibility. If your mother was like so many of us in the tristate region, she was overwhelmed with shock and sorrow. And, if she was like me (and many others with close ties to the city and the financial district) there was also unspeakable rage, such as we never have felt before (even after the Florida State Supreme Court decision in 2000). For me, there was no easy place to channel my emotions. I know I was not sleeping or eating well during those days. I'm sure my stress hormones were sky high. And high stress hormones (cortisol, etc) can inhibit your immune system and lower your resistance to microbial pathogens--both viral and bacterial. In a susceptible individual, this could easily lead to respiratory infections that could evolve into pneumonia.