So in this case the body is dominated by a person who clearly doesn't want the domination removed. How is that different from a spirit who doesn't want to leave the possessing body?I would consider a charmed or frightened condition sufficiently different from possession to require separate analysis.
The way the spell works to me is..... Possession and Domination are conditions that are applied to a creature, they do not replace the creature. Its also why a possessing ghost can't be target by an attack....because the the attack is still targeting the OG creature, not the ghost.
So if I have a spell that can cure a condition, whether its possession or charmed, it is targetted at the OG creature. And since most restorative spells don't require attack rolls or saving throws to work....neither does Dispel Evil and good.