Hi there,
My dad passed away a little over 2 years ago from pancreatic cancer. They wanted to do the whipple on him but the tumor was wrapped around a major artery so they were not able to remove it. Chemo kept the tumor from growing too much for about 8 months, but then we learned it spread to his liver. Keep in mind that everyone is different. Once my dad's spread to his liver, he tried gemzar for chemo but it just made him too sick. That was July, and he was able to live a semi-normal live until the end of the year, with a few bouts of pain, although was was really tired. In early January we learned it had spread to his stomach and he went downhill fast from there. He passed away in early February.
I know you are kind-of looking at a timeframe so I wanted to give you that info, but of course everyone is different.Good luck and if your dad is up to it, I'd recommend keeping trying the clinical trials. Some day soon they are going to find a cure for this awful disease.