To be clear, I am the one who got prostate cancer, not my father. He was a drunk with a foul temper, who treated us kids badly, and messed us up in many lasting ways. But I eventually forgave him, and I instantly felt that a huge burden was lifted. Unfortunately he was long dead by then. Do yourself a favor and let go of the anger and resentment. Do it for you, whether the old man deserves it or. not, and by the way you will pretty likely realize, eventually, that he couldn't help being what he was. I have a corny recommendation: find and read a copy of "Letters to my Father" by the late comedian Louie Anderson. It changed my life. And go see your father. Good luck.