A:
You must be dutiful to your mother and show her kindness in your deeds and sayings. You must explain - without shouting at her - that
a woman is not permitted to be unveiled in front of her husband's brother-in-law. You should read this Fatwa to her; if she follows it, this will be alright; if not, order your wife to disobey your mother regarding being unveiled before your brother-in-law and prevent her from sitting in his presence.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.