There is an excellent clinic that I know of in Germany, if your father is interested. A very good friend of mine who had stage 4 throat cancer, is 100 percent cancer free after ten years. His close friend Cher (Bono) recommended this clinic to both Brett and Farrah Fawcett, but unfortunately Farrah waited far too long before she sought out treatment.
Your love for your father is so beautiful. Such pure father/daughter love. You are extremely fortunate to have such a loving relationship with your father, and I hope that you share many more years together.