Jack's mother once nourished him when he was a boy, feeding him with love and affection. But now that he's gone, killed in action in the trenches, she can no longer do so. Instead, she is reduced to receiving spiritual nourishment from the “gallant” lies told about her son in the letter she has received from the colonel.

She will cherish this letter for the rest of her days, because the information it contains, though palpably false, does at least reinforce her unshakable belief that her late son was brave and glorious. In that sense at least, the letter will provide some degree of consolation.

Although the precise details of the letter are never revealed—other than that Jack “fell as he'd have wished”—it's patently obvious that the colonel's letter made Jack out to be some kind of hero. In actual fact, he was no such thing; he died accidentally after stepping on a land mine. What's more, he was regarded as “a cold-footed, useless swine” by the officer who brought Jack's mother the colonel's letter.

Little wonder, then, that Jack's mother is the only one who cares about his death. To her, he will always be a hero. To his former comrades, however, he will always be that useless soldier who was forever trying to get sent home.