You don't need to be a doctor to see when things look bad. You don't need to be a plumber either to see there's a leak under the sink. Use your common sense, man.
You need to be Steve's doctor to be able to know whether he is going to die from his condition or not. We know nothing about his specific situation.
edit: of course pancreatic cancer is one of the worst to have, most people know that. However to be able to say that "it's curtains for Steve", you would have to have a lot more information on his specific situation that no-one on this board possesses. There are people who survive this type of cancer and liver transplants, so why not Steve Jobs?