Martin Shoemaker, over in Dean's comments section, pointed out I hadn't come up with anyone to be the agents in this typology, and of course he was right. So here goes:
•Wayne is a boarder at the Big House. He used to take up 15% of the floorspace in Aunt Edna’s lonely room in the Big
House, but that was really all right, because he would argue Grandpa into letting her have a much bigger room, and even if he couldn't get her everything she wanted, at least Wayne kept her company and would stand up for her when the
rest of the family picked on her. Now and then he would win arguments with Ted for
her, saving her a great deal of stress and anxiety, and Wayne was always after Larry about getting a look at the bank
statements.
But now that she’s moved out, he wants her to give up that
room in town, move into his new little house with him, pay him rent, and
let him handle everything, and it's by no means clear that he'll handle it better than she will.