Daughter,
I think in your heart you know what your dad needs....if he is a private person, then maybe he prefers to remain that way. It's a tough call...and you are doing all you can by just being there for him. My mom was extremely private, and I am complete opposite! I want to know details, and rip everything apart until I'm aware of situations. My mom, on the other hand, prefered to keep her head in the sand and remain in the dark about cancer as well as most other things in her life. Everyone has their own way of dealing (or not dealing) with things, and now, after a long struggle, my motto is.." to each his very own".....just know that you can't do anything to make him feel or think differently, and be there for him, even if all you can do is hold his hand and say I love you.