How does Stephan Kelman present Harri as a vulnerable character in the novel

Being from Ghana and still a child, Hari is vulnerable to the world of a child near teen as well as the world of a visible immigrant. The protagonist/narrator is an eleven-year-old schoolboy newly arrived in London from Ghana. He is a good kid who has managed to retain his innocence even in the face of peer pressure, violence, and the attendant darkness of the modern world.