Slaughterhouse-five #4

In Slaughterhouse-five written by Kurt Vonnegut, many times the book seems to reference back to itself in a way. Ill explain two instances that played some sort of importance to me. The first was when he referenced that he wasn't going crazy and the second was when he was talking about a German talking to them about war real time. 

The first instance was after, "He was going crazy,"(100) and then wrote that it had to do with his relationship with his father and the things they did together. It lists two specific instances the YMCA and the Grand Canyon both of which Vonnegut previously mentioned. Why do they lead to his craziness? Truly I'd like to understand that more. What does this signify about his relationship with those around him?

The second instance was when the German said, "We had forgotten that wars were fought by babies,"(106) which gave a reference back to his old war times friends wife. I found this significant because I wonder how much Vonnegut is including in order to build up what he said he would do for that woman. Does this clarify in a way that this book in no way will promote war? Again, I guess I will come to find out!