Both Mr. Woodifield and the boss lost their sons in the war. The sense of loss had to be immense for both men. No parent should ever be placed in a situation where he or she outlives their child. The stages of grief are well documented, and most sources agree that there are five stages of grief. Those stages are the following:
The author doesn't give readers a lot of details about how the boss and Woodifield mourned the loss of their sons. We get some information about the boss's process in a lengthy paragraph about halfway through the story, but we get almost zero information about Woodifield's process.
We know that more than six years have passed since the deaths, and we see a Woodifield that has gotten himself to the point where he can talk about his son without breaking down in tears. In fact, he's able to talk about the burial location in a positive light.
"The girls were delighted with the way the place is kept," piped the old voice. "Beautifully looked after. Couldn't be better if they were at home. You've not been across, have yer?"
Woodifield hasn't forgotten about his son. The loss still causes sadness, but he has accepted the loss and doesn't resist the reality of it. He isn't struggling to deny the loss or undo it somehow. Woodifield isn't harboring anger over it. Time has helped soften the hurt.
The boss hasn't been able to move into that final stage of the grieving process. He still experiences crushing sadness at the thought of his son. The mere mention of the grave sight is revolting to the boss. We are told that for years, only the mere mention of his son's death would cause him to begin weeping.
In the past, in the first few months and even years after the boy's death, he had only to say those words to be overcome by such grief that nothing short of a violent fit of weeping could relieve him. Time, he had declared then, he had told everybody, could make no difference. Other men perhaps might recover, might live their loss down, but not he. How was it possible?
A reader might be able to make an argument for the idea that the boss finally enters the acceptance stage in this story. It would be just before the fly arrives. We are told that the boss didn't feel the way he normally felt. He wasn't weeping. The boss pulled his hands away from his face. No tears had come. The boss thinks this is strange, because the sadness has been so severe for so long, but this absence of crushing sadness might show that the boss has entered the final stage which Woodifield entered much earlier.
the boss covered his face with his hands. He wanted, he intended, he had arranged to weep....
The boss took his hands from his face; he was puzzled. Something seemed to be wrong with him. He wasn't feeling as he wanted to feel.
The boss's torture of the fly at the end of the story, however, might be an indication that he has not come to acceptance, but is instead acting cruel out of grief or distracting himself so as to not feel the sadness.