I mean, if they’re not married and he charged her rent, how’s that much different than having a roommate? Why would she be entitled to ownership of the property just because she paid for a place to live, barring marriage or common law? There’s something to be said about being up front about your financial situation sure, but how she could expect equity out of the arrangement is a little asinine, unless she helped pay for repairs and upkeep (aside from basic cleaning/chores).
It’s obviously all a made up scenario, but imo time is a significant factor here. If she lives there for three years then it’s likely that she’s helped with repairs etc, so imo should be entitled to equity in some respect.
Seems a bit shit to treat a partner like a roommate.