Did you get to do the whole, choose your floorplan deal? My friend did when her family bought a new house and she said she got to add a reading nook to her room.
I think religion is an entirely personal matter. If she made her peace with whatever deity she observes then I don't see a problem with not telling her parents. On her dad dying, I think it's better to send him off with happy memories then to needlessly make him worry or stress (assuming of course he knew to some capacity that he was dying and it wasn't an accident or something).