A wife calling her husband 'My son'

Q 1: What is the ruling on a woman calling her husband "My son" while joking with him? Is this considered Zhihar (a woman likening her husband to an unmarriageable relative)? If so, what is its Kaffarah (expiation)?

A: It is Makruh (disliked) for one of the spouses to liken the other to an unlawful relative to marry, such as a mother, a sister, a father, a brother and so on. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.