Well hopefully I can help with your worries. I was diagnosed just over 2 yrs ago with Stage 4 COPD and here I am! I finally went on 24/7 Oxygen 6 months ago, yes taken by ambulance to the Hospital being diagnosed with Pneumonia, clasped lung and then with in 24 hrs Lung Cancer Stage 3a. Here I am today, writing to you, in remission, having had a new Pulmonary Function Test (PFT) showing my lung capacity / function remains as it was 2 years ago. Not bad and I plan on being around a long time. Yes, should your father get his affairs in order, of course, but so should you in my eyes, just how I have told my daughters who are 34 and 38 years of age. Why?, no body knows when something will happen to them, being an accident, illness or just being in the wrong place at the wrong time. It's all about taking care of yourself. Medical advancements are also showing up, so a positive attitude for the next new medication or procedure might be something really awesome.
As for how you could deal with this, live one day at a time, learning how to trust your own choices, building your self confidence. While making them you can think about "what dad would do or say" what was it that I did last time for this type of thing. Then if you wish, write it down, then call and see what dad thinks if you wish, thus learning to trust yourself for again no one knows how long any of us will be on this Earth, hopefully a long time. It makes me so happy when one of both of my daughters calls me and tells me that they handle something they normally would have called on to ask for my advice or tell them what to do. Learn about this disease so hopefully when or if your dad might need your help, you are ready to give it, thus keeps your mind busy and not on what will happen one day, just which day, no one knows. I wish your family well, it's a learning experience for all of us to say the least. As others have said, just come back if there is anything else that you wish to ask.