He was using his body language and gesticulation to make a digresion and push the speach in a new direction for a brief amount of time. Digresion is commonly used in public speaking when one is giving and example, introducing new topic, bringin a guest in, and so on.
When Manual talks about his granny, he tells us a story about an insane old woman. His grandmother was a vivacious and cheery old woman. She had spent her days cooking amuse the troops of the government that were stationed around the Golden Bridge.
As for why she is insane This part of the text justifies it: <em>"She was crazy," Manual insisted, "because she only charged them for the cost of the food she cooked, and she didn't earn a penny for all that work.“</em>
So, to Manual, making food for the troops was crazy because she didn't earn any money from doing so. This part of the text most likely tell us more about the narrator than about Granny.
It can be perseverance, courage, maybe even hope.
