Under the Sunlight with Bentou Boy

Nonomura Heita, a high-schooler, takes care of the last boarder left at his grandfather's house after his grandmother passed away. The boarder is a translator named Miharu, who insists that Heita make a bentou for him every day. Should such a wifely duty be given to a high school boy? Or will the duties someday go beyond just making bentou?