I would have national grid check the meter and make sure it’s not charging her for an additional shared space or something. 400 seems high to me for a 1br. That being said, 68 at all times sounds excessive. I turn my heat to 60 and leave for the day. Turn it to 60ish at night. I’ll “blast” it to 68ish when I’m in the living room or just around. In my opinion leaving the heat at 68 around the clock sounds incredibly wasteful but luckily it will be an easy bill to reduce. Turn it down when you leave and before bed. Curtains open towards the sun during daylight and closed away from the sun or at night. Weather stripping/door sweep to windows and entrances. A couple throw blankets on the couch. Comfy sweatpants and long sleeves. She could very easily reduce the bill by 30% with minimal if any sacrifice.