I just finished Ellen Klages' Green Glass Sea, which, SPOILER, has the mc's dad die 3/4s of the way through, and ends with the bomb going off at Hiroshima. However, the characters aren't aware of what's going on, as its just background noise on the radio. They feel fairly secure at the ending, on a nice family vacation, the girl whose dad died feeling some resolution and part of a new family now. But of course, the Hiroshima mention is hugely sobering and shades everything for the reader. And beautifully written, I must say.
Though I wonder if the rules for historical fiction are slightly different.