I think the casket is a symbol of death and it is also a symbol of cruelty of the narrator that he took Doodle to see it and touch it to emphasize that they thought he was going to die so needed to be brought face to face with it.
In the first excerpt it is this sentence:"It was a difficult moment, but I did what seemed right, which was to say, "Of course not," and then to take her onto my lap and hold her for a while."Here we see that the author is really not comfortable with the question his daughter asked him and thus he lies to her. You can see the pain he feels in just one sentence and the horrors that are hidden behind. One day he may tell her but not then."They would discuss their experiences right up to the time of battle and then suddenly they wouldn't talk anymore."This sentence in the second excerpt show the unwillingness of the usually boastful people to talk about the war in detail. The author notices that they don't remember and it could potentially be that they wanted not to remember. Unconsciously they blocked the horrible things they had done and seen. c;
