My Dad was told in November 2001 that he had 3 months left to live. I admire him so much because a) that alone can't have been the easiest thing to deal with b) he didn't die after 3 months so it seemed to always be looming over us - when it would happen.
I don't really know how I coped to be honest. He died in April 2005, I was working hard for my AS Levels. I think I managed by just carrying on as usual, I knew that my Dad would've wanted me to do well academically and keep busy rather than becoming introverted and sad. I completely understand that people may experience grief in many different ways and that how I managed would not work for everyone.
I think initially my Dad just accepted it as there was very little, if anything, that he could really do about it. When his health started to improve, I think he almost told himself that he wasn't going to die and I firmly believe that this is partly why he made it to 2005. If you accept that you're going to die, are you not already letting the illness win? I understand that some illnesses are terminal and it may be better for all involved to accept that but if there's a small chance that you might not die, I really think you need to keep positive.
In the end though, I think my Dad gave up because he had been through so much. 2 battles with cancer, a stomach bypass, various other medical procedures - when the cancer came back for the second time it was much worse, his breathing was terrible and the doctors feared the tumour was entering his bloodstream. He said that he didn't want any more treatment. I think he'd definitely had enough and in a way it probably was a benefit to all of us in some way. His standard of living wasn't great over the several years he was ill and that placed a lot of stress on my Mum, who would go to see him in whichever hospital he was in (Birmingham or Leicester, probably 2 hour round trip) each day. I guess you could say it was a bit of a relief to see him go and for him to have decided that then would be the time.
I don't remember properly crying except for the first time I got to the hospital after he had died. I think I'd accepted that my Dad wasn't at all healthy ever since he'd had cancer the first time round and it was just my way of thinking.
I know I've babbled A LOT but I do get quite reflective about my Dad at times and I guess this is one of those times. To answer the Q in short, I don't think you can answer it for everyone; it depends on the individual and how satisfied they feel with how they've lived their life. If you feel fulfilled, then I think you're more likely to readily accept it than if you are constantly wishing that you'd done A or B.
Sorry if this makes little sense, I'm tired, a little emotional and feeling extremely babbly!