Who is Guiseppe from History: A Novel and what is their importance?

Little Giuseppe has named himself Useppe because of his childish speech. He is a tiny, sickly child who never does catch up to average in size and health. He is a child of rape and war, and comes into the world under disadvantaged circumstances. His mother, who is his protector and keeper, takes second place in his life to his beloved older brother, Nino, who only shows up occasionally for play and bonding with Useppe. The author implies that Useppe longs silently for his brother for most of his life.