Why does the mother-in-law always regard her daughter-in-law as a member of her family?

A son is a son all his life, and a daughter-in-law is likely to divorce. Being a member of the family can only show that her mother-in-law is stupid and her face is ok.

In addition, interpersonal relationships are mutual. Daughter-in-law is kind to her mother-in-law. Under normal circumstances, a mother-in-law will be kind to her daughter-in-law. Don't expect your mother-in-law to give as much as her mother.