The man walks along the beach while the boy sleeps and when the man returns, the boy is sick. The boy vomits and apologizes, and the man tells him he hasn't done anything wrong. The man holds his feverish son through the nights, terrified that the boy is dying. He works to keep the fire going and examines their food for anything suspect. He gives the boy medicine from the first-aid kit, but nothing seems to be helping. He vows that he won't let his son die alone.
Then, one morning, the boy wakes and he asks for water. He's ready to eat again. The man asks if he remembers being sick. The boy says he remembers and that he had some weird dreams, but doesn't want to say what they were about. The man stares at his son. The boy asks him to stop looking at him, but the man can't.
This section, like the rest of the novel, illustrates how much the man loves his son. He comes so close to losing him and is enraged at the thought of having his son taken from him. He keeps his promise, though, making sure that he doesn't leave his son because he refuses to let his son go into the darkness alone.
This section also contains a lot of fire imagery, referring multiple times to how the father tends to and rekindles the fire. This physical fire stands as a metaphor for the fire that he and the boy talk about carrying within them. The father fights to keep both his son and the fire within the boy alive, and McCarthy uses the physical fire to emphasize this recurring theme.
For the first time, the boy reveals that he does keep some of his thoughts private, even from his father. The boy doesn't want to tell his father about the dreams he had while he was sick. While we don't know what the boy dreamed about, the implication is that the boy is keeping his dreams a secret to save his father's feelings. Maybe the boy's dreams would scare or depress his father. Or, instead, maybe the boy is simply shy, or maturing. He gets uncomfortable when his father stares at him. This, too, could represent a part of the boy's growth: he needs his father to care for him but at the same time, he's craving a bit of independence, too.