Second Margaret's comments,

Welcome to OCF...you have found the right place for answers to your questions as well as emotional support.

Many here with stage 4 diagnosis and have undergone "curative," not palliative treatments. You need a second opinion (and perhaps a third) ideally at a comprehensive cancer center (CCC.)
Perhaps there is more than you are telling us, but spend some time reading and you will find lots of folks in the same position as your father and they are surviving.

Tell us more and we will try to help, but also, spend some time researching this website. Read, read, read, and you will become a very informed advocate for your dad.

Deb