farrocks
A daughter and daughter in law are one and the same as far as relationships. A daughter in law is equal to a daughter.
In light of your comment Farrok:- Clearly yoo don’t attend hoRav Yisroel Reisman’s Motzei Shabbos Nach Shiur {or perhaps you do, and you seriously disagree with him}.
About a year ago, he said, this wish often given to a new Bride/Groom by the future in-laws:- “oh! You shall be to us exactly like a daughter/son” is the most awful wish. Bear in mind how the young Bride/Groom feels:- S/he has 2 biological parents who have been raising her/him for the past 2 decades {or longer of s/he spent a long time on the Shidduch [crisis] market}, and suddenly this middle aged couple whom until say a month earlier, s/he had never heard of, are trying to be on equal with her/his biological parents.
They may say:- We will be most happy to welcome you into our home & lives & Shabbosses, but not to be a replacement for her/his biological parents.
As an aside, one does not sit Shiva for in-laws, even if they were your in-laws for over a generations’ worth of time.