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).