All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is an obligation to abide by the Sharee’ah ruling in this regard, which is that the new-born should be traced back to his/her father and to his/her grandfather from his/her father’s side and not to his/her mother or to his/her grandfather from his/her mother’s side. For more benefit in this regard, please refer to Fatwa 90364.
Moreover, we have already clarified in Fatwa 85803 that tracing a person back to other than his/her father and his/her grandfather from his/her father’s side is contrary to the Sharee’ah.
Therefore, you may show the above two Fataawa to your husband as they include the religious texts on this matter.
Allaah Knows best.