Responses
On the off chance you’re talking about the (seemingly) random letter in chapter 12–It’s a letter FROM Callahan TO Johnny’s mother. He had bought into Johnny’s story and wanted to reassure Johnny’s mother that he was still alive after all this while, but the letter he had sent had come back to him because she was no longer around. Either that, or it was never sent in the first place because he realised Johnny wasn’t so truthful
God i might be dumb but i think i'm missing chunks of plot here. Thing either didnt get properly addressed or the reasoning is too hard for me to comprehend