Little Lord Fauntleroy (1980)

Suddenly, into the poor, but happy lower-class Manhattan home of the widow Errol and her son Cedric, aged about nine, comes an agent from Cedric's mysterious grandfather, the Earl of Dorincourt, asking them to move to England so that Cedric can learn aristocratic ways and inherit the vast estate. Cedric's mother consents with misgivings, especially for having to live in a house nearby, rather than in the castle with her son. The Earl proves to be a penurious misanthrope, hated by almost everyone who knows him. But from the beginning, Cedric sees only good in him, can't imagine that he would ever treat his tenants and villagers poorly, and wins their hearts with kindnesses, giving all credit to his grandfather's wishes. Soon the dour old man finds that he loves this cheerful little boy so dearly, that he wants to live up to this new image of himself. The sudden appearance of a vulgar, ambitious American claiming that her son is the true heir to the title is a more grievous blow to him than anyone would have thought possible.