*hugs to Mistress Jo for her Uncle's complete recovery*
It turns out that my father's co-workers were not entirely accurate when they described his accident. After speaking with my parents today, I got the full story:
Dad, who is a carpenter, was prying at a board with a crowbar. The crowbar slipped, and he fell backwards onto a footer. (For those of you non-carpenter types, a footer is a block of wood approximately twelve inches in height which is used while constructing the frame of a house.) Taking a block of wood to the lower back is never pleasant, and it was the pain of his sprained back that made him pass out. When he came to, he tried to continue working, but the pain made him dizzy and ill. Finally, his boss took him the ER, where he spent seven hours waiting to be X-rayed. Turns out that he didn't break any vertebrae, but the scans did reveal that he has pretty advanced arthritis. He's been told to rest up for the next couple of days; then I'm sure he'll be on Celebrex or some such for the arthritis pain he's been too stubborn to acknowledge until he hurt himself. Best of all, worker's comp is grabbing the hospital bill...
My grandfather continues to be in good health and spirits; my grandmother continues to be insane and evil; and the family as a whole has finally started to recover from the flu.