Is the mother of the stepmother a Mahram to the sons of the father's first wife?
mother of the stepmother is not regarded as a Mahram to the sons of the first wife. Accordingly, she has to wear Hijab (veil) in front of them, and she is not permitted to travel with them or to be in Khulwah with them without a Mahram. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.