This quote comes as the father tries to adjust to the new situation that faces him and his son. Having spent so long desperately looking for food and trying to survive, they eventually end up in a hidden bunker with an unbelievable amount of tinned food and supplies. Such luxury had been beyond his wildest dreams. The quote applies to the man's expectation that he and his son were going to die from starvation, but now of course his worst nightmare is not going to come true, at least for the next few days, and he feels a need to sit down and think about the change in circumstances that have happened to him and his son. They now have hope again rather than the despair that caused his wife to go and "hide in the woods" and kill herself, effectively opting out of society and life. Note how he responds to this situation:
Finally he rose and went to the table and hooked up the little two burner gas stove and lit it and got out the frying pan and a kettle and opened the box of plastic kitchen implements.
Even though he was expecting death so strongly that now he has a chance at life he doesn't know how to respond, eventually he decides to simply get up and make breakfast for himself and his son, engaging in a "normal" activity that is about survival and providing for himself and his son's needs. The quote therefore concerns the way that the man had expected to die and how he needs to adjust his thinking to the chance of survival and life again.