Yeah he hid it from most of the people he worked with, but he had cystic fibrosis. Hell of a disease to hide; I have it myself and it requires a lot of maintenance and frequent week long hospital stays! That said, a shame he died from that freak accident because nowadays (like the past two, three years) the drugs for the disease have gotten astronomically better, and in all likelihood he would live to a ripe old age with it just fine.