Hi-
I am so sorry about your Dad. I can sympathize with how you are feeling. My Mother was diagnosed with stage IV colon cancer when her colon burst. They also found large tumors in both lobes of her liver, and a spot on her lungs. She had 6 surgeries in three months (colostomy, historectomy, etc), received chemo for 24 weeks, was told that the tumors were still not resectable, and was told to get her affairs in order.
We lived for six months under a dark cloud, feeling that there was nothing more that could be done for her. Then, last summer I received a newsletter from our local medical center, with an article about a new treatment for stage IV colon cancer that had spread to the liver. The treatment involves injecting radioactive beads directly into the tumor. We immediately booked an appointment at the best cancer care facility in the area.
We are lucky and live in a metropolitan area that is well known for cancer care and research at several local hospitals. The Dr. that we saw was really disappointed that she had not received treatment for so long, and showed us how much the cancer had grown. To make a long story short, the Dr. enrolled her in a clinical drug trial, and she has now had about six months of relatively pleasant life experience that she would not have had otherwise.
I do understand that there is a time when the fight is over, but if your Dad still feels like he has fight left, I would strongly encourage you to seek out other opinions. While I know that we all have to rely on the advice and expertise of the Dr. during cancer treatment, there are some Dr's that are not willing to try new things, and some that are. It sounds like your Dad has been through so much and I know how emotionally exhausting the experience can be for everyone. I wish you the best, and will keep hoping for you.