My sister had done Kateb al-kitab (registered married in Islaam) but had not had sexual relations with her husband as they still had not moved in together as they had planned to have a celebration first. They broke up because of certain problems but now they have solved the problems and have reread the Faatihah but have not redone the Kateb al-kitab. Is it permissible for my mother to reveal her hair to my sisters fiancé even though they haven't redone the Kateb al-Kitab?

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. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The mother of the wife is a Mahram to her son-in-law as soon as the marriage contract is concluded. Allaah says when mentioning the women who are unmarriageable (Mahram) (interpretation of meaning): {…your wives' mothers}[4:23]. So Allaah, The Most-High, did not condition for the wife's mother to become a Mahram, on the marriage being consummated; hence this is an evidence that she becomes a Mahram as soon as the marriage contract is concluded. Therefore, you should know that it is permissible for your mother to show her hair in front of this man. It should be noted that marriage is legislated for noble objectives, so any obstacle that might hinder its realization or delay its finalisation should be removed. Indeed there is much good and blessings in making marriage easy.

Allaah knows best.