I'm really sorry to hear about your Dad, CdnBison. Cancer is indeed a devastating diagnosis, but hold on to hope.
Cancer is such a scary word, and when people hear it they tend to only think abou those who passed away, rather than all those who survived/are surviving the diagnosis. I feel very strongly that keeping a positive attitude (as hard as it may be) is integral in the body-mind healing process.
Take care of yourself, CdnBison. We're all thinking of you and and sending healing thoughts your Dad's way.