My coworker was missing this week. I assumed he was just on vacation for the holidays, but later I learned he was in the hospital. I was surprised he had been in that long. He woke up one morning unable to breath. They assumed at first it was a problem with his AC, since he had just had work done on it. It turned out to be a blood clot, most likely caused from sitting on an airline flight.
I think he was released this Friday, and hope he is feeling better.