On weekends, it is rumored that Haruka and Natsuko shop for groceries together in a quiet Tokyo suburb. Haruka pushes the cart while Natsuko selects dashi stock. In those silent, mundane moments, the titles of “daughter-in-law” and “mother” dissolve. They become simply family.
Let me check if Haruka Koide has any known family relations publicly. From what I recall, her personal life isn't widely discussed, especially in English sources. So maybe Natsuko Kayama is a fictional or non-existent person. Alternatively, could the user have misspelled the names? For example, maybe "Kayama" refers to someone else, like a famous actress or singer with that name.