Unfortunately, pancreatic cancer is a truly horrible disease (as you are already aware, I'm sure). Even after bypassing the stomach and the bile ducts, many pancreas cancer patients will still experience significant upper abdominal and/or back pain. In most cases, this pain can be eased with narcotics, although it may be necessary, in some cases, to have a radiologist or a GI doctor inject alcohol into the nerves behind the pancreas (celiac axis block) to ease the pain.
Unfortunately, patients with incurable cancer don't always follow the same clinical course, and so I am always reluctant to offer specific scenarios (including how long any individual patient will live). In most cases, however, patients with advanced pancreas cancer tend to lose their appetite and stop eating, and they do generally develop progressively worsening fatigue and weakness.
I hope that, at a minimum, your wife can find relief from her pain. I wish that there was more that I, or her doctors, could offer her, Sir.
Sincerely/ Robert A. Wascher, MD, FACS
http://doctorwascher.com