Is the husband of a person's foster mother a Mahram to his daughters?
My foster-mother married a man other than my foster-father. Should my daughters wear Hijab (veil) in the presence of this man?
It should be noted that this man is the husband of their foster-grandmother. Should we call him uncle or step-father?
The husband of a foster-grandmother is like a step-father. So your daughters do not have to wear Hijab in the presence of your step-father (Part No. 17; Page No. 371) even if he is not your real foster-father. Your daughters are step-daughters of your foster-father. It is not mentioned in the Shari`ah that a step-father or a husband of the grandmother is called a paternal or maternal uncle. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.