Depression in Terminal Cancer

I'm sorry I haven't answered sooner. I was unable to write since I celebrate the Jewish New Year.

Of course your father is "down" but I would not called him "depressed." He needs to mourn. He is losing more than he ever imagined and that requires a mourning period that, during the first stages, looks like depression. While there is no way of knowing how much any particular person needs to mourn his own life (or life stye, since there is really no way of knowing how long he will actually live) he does need to be allowed to mourn in the way that he feels right, and for as long as he needs to. Letting that happen will actually make that period shorter.

He feels ill and "not right." He does not not want to hear anybody tell him that he has mental health issues on top of his other health issues. He does not need a mental health professional, rather a quality of life professional. When I work with people in this situation I find that often the family also needs to be involved in order to help the patient work through the issues, and because they are actually working through many of the same issues.

Focusing on quality of life can be looking at the loved one's life and appreciating all with good that the family has gained from having him around and what the loved one want to make sure is left before he goes on. Once those positive outlooks find a foothold, more positive experiences can be built up and appreciated.  

You are right about wanting him to have as much joy in life that he can. The positive attitude can increase his resilience and chances to live longer. But it can only be achieved by allowing him to start where his is mentally and find and build on the positive joyful moments that he can find now.