It's more that Corazón is a descendant so he belongs in the house - along with other people he brings in - and the ghosts didn't want it sold.
Well, I mean...you shouldn't be alone. Being alone is...pretty lonely. And I know what it's like to be alone, so I don't really want other people to have to go through that.
Fair warning, Prudence is sometimes a bear. But she's mostly harmless. When she's a bear. The rest of the time, she's terrifying.