Who is Morgan Moreen from Tales of Henry James: The Texts of the Stories, the Author on His Craft, Background and Criticism and what is their importance?

Morgan Moreen is the twelve-year-old boy that Pemberton takes on as tutor. The youngest in a family of pretentious, extravagant Americans who live flamboyantly and dishonestly, the child recognizes them for what they are — morally bankrupt pretenders. Morgan is more intelligent than other members of his family, but even more important, he has an inborn sense of honor and moral code that is far superior to his family's. He is so noble that when his beloved tutor is offered a better job, Morgan urges him to take it for his own good, even though it will leave the boy alone with his despicable family.