PS. I should add that this story, in it's own way, reminds me of one of Robert Heinlein's shorter stories, /Requiem/, where, again, a man did what he had to do to keep the world he loved, and those he loved, safe. Totally different stories, but with a somewhat common theme.
Heinlein has always been one of my favorite writers. I met him at a Sci-Con in Norfolk a couple decades ago. When I asked him to autograph a copy of 'Starship Troopers' I was the only one he made an exception for. Normally, he requires you to donate blood. Since I'd had Malaria, I was prohibited from doing so.
Anyway. I'll have to look UP Requieum. I don't think I've ever read it.