My heart goes out to you and your dad for all you've been through. There are different types of pancreatic cancer. I'm familiar with pancreatic adenocarcinoma, the most common one, which is what my dad has. When it spreads to another organ, it's stage 4. Stage 4 pancreatic cancer has almost no five year survival rate. It's my understanding that it has the worst outlook of all cancers. When my dad was diagnosed, they told him based on others that he might have six months to live, and maybe a little longer with treatment. There's never any way to know for sure. It's now nine months since his diagnosis. He did receive treatment for a while, that failed, and he chose not to continue with treatment, opting instead for Hospice.
Here are a few resources for more information:
Hospice has been very good at managing pain. There are many good days. The Hospice doctor said you never know for sure how long. So we take one day at a time and make the best of each day.
Each case is different. So there's no way to know what's going on with your dad without talking to the doc. Best wishes to you.
The standard chemotherapy used since the 90's has been Gemzar (gemcitabine), which is still used for people who can't tolerate the alternative combination-- FOLFIRINOX, which is harder on the body. Then there are also clinical trials, and some other combinations they can try.