Dear Brat
I too, am sorry for your loss. I think loss of bladder control is fairly common (usually bowels, too) at death. I am sure the co-workers were not focusing on the wet pants, but were more concerned about your father. The sneeze may have caused a valsalva response, but most likely it didn't actually kill him, he probably would have died, especially given his symptoms earlier in the morning. Condolences to you and your family.
Take care.