Very similar situation here. It's been 6 seasons since I hunted. I decided about 11 seasons ago that when my dad could no longer hunt, I was done. It was the last thing he loved to do that he was able to still do and the only thing left that we could do together. Even with me driving to within 20 yards of his blind ( which I furnished with a heater and a comfortable chair) it eventually was too much for him. Getting up early, in the cold, the walk to the blind. The last year we hunted I was able to kill a deer and convince him he had killed it. He knew it was his last year and he wanted to kill a nice one. So he did.
The last several deer I killed I found myself feeling bad. Ashamed almost. The times I hunted and didn't kill a deer was because I didn't want to kill a deer. I do miss the woods, but I will never kill another animal unless I absolutely have to. I understand the need for deer populations to be checked and I have no quarrel with legal, ethical hunting. I'm just not going to do it.