Francisco is becoming madder by the minute; he's convinced he'll be shot through the heart, so Mario now lives in his sleeve pocket. Hierarchy breaks down as soldiers die. Finally, on November 14, the Greeks corner the Italians. A chaplain picks shrapnel out of Carlo's arm without anesthetic and then sends him right back out. Carlo's hate for puttees has now spread to his entire uniform, which seems to abrade his skin. Both Carlo and Francisco skin animals and wear the hides. Another division left rusty tanks behind, but the Greeks managed to repair them and now use them against the Italians.
Carlo's hatred for his uniform as a whole illustrates how the Italian army dehumanizes and abuses its soldiers in every way imaginable. It destroys their bodies not just by putting them in harm's way, but also by giving them uniforms that destroy bodies in other ways. By skinning the animals for warmth, Carlo and Francisco suggest that the only way to survive is to reject the army altogether.
Over the next month, the division is cut off from all others. Men put the brains of dying mules in their helmets to keep warm. They try to keep to the high ground to stay warm, but the wind is bitter. Every morning, they discover new men who died in the night. The Albanians begin to help the Greeks, and Francisco talks only to Mario. Men die of gangrene, and Carlo thinks that Greece should win if it will end this war. The snow makes it so they don't recognize landmarks, but their maps don't match anything on the ground anyway. Mussolini comes to visit, but Francisco and Carlo don't stand when he walks by.
Note that Francisco and Carlo aren't punished for not standing for Mussolini. This suggests that it's possibly not worth it for Mussolini to make a fuss out of it, or it's possible that Mussolini is too caught up in himself to notice. The numerous elements that go wrong and work against the Italians show just how horrendous war can be--but also indicate that some of that horror comes because of the poor decisions the Italians made in the first place.
Francisco writes a letter to his mother and gives it to Carlo to deliver to her if he dies. He tells her that Carlo is a good and true friend whom she should think of as a son. He says that he's too weary to care if he dies and feels as though he's been dead for months. Carlo laments the things he doesn't tell Francisco's mother when he delivers the letter to her in April.
By writing this letter to his mother, Francisco accepts that he's going to die. This suggests that Carlo's letters are also written with the knowledge that he's going to die, and that they're a way for him to find a sense of peace in death.