Who is Uncle John McAdams from The Favored Child and what is their importance?

Uncle John is the man who claimed to be Richard's father throughout the years. Uncle John leaves Wideacre after the villagers burn the house, kill Beatrice and cause the death of her brother Harry, in an attempt to raise enough money to put the estate back to rights. He succeeds, and it's John's money that provides the basis for farming supplies to put the estate back on a money-making level. It's also Uncle John who tells Richard and Julia that they are actually brother and sister, and that he is not Richard's father but that both children were born of an incestuous relationship.