karen,
I'm very sorry to hear that your father's cancer has progressed so far. I lost my father to cancer a little over a year ago. And someday I may be in your father's position. All I can say is my father knew I loved him on the day he passed and my son knows that I love him each and everyday we have together now. Your father knows how much you love him.
Stay stong and I'm praying for you both right now.
Tim