Home on furlough an hour and he's already gone through a pack.
The message, of course, is that the Father needn't mail his son cigarettes, but should come home with them NOW, because there's a BIG SURPRISE Mom isn't going to reveal . . . although she already did, I suppose.
Given the age at which most women had kids, wouldn't she be in her mid-40s? Apparently at that point women just went into grey-bun-and-apron mode for the rest of their lives.