The ruling on a brother looking at his brother's wife

Question:
Is a man’s brother’s wife forbidden or permissible?

Answer:
Yes, looking at a brother’s wife is intentionally looking at her face or some part of her body, and this is forbidden because she is a non-mahram (a woman with whom marriage is not permanently prohibited) and is forbidden to him. Therefore, it is not permissible for him to look at her face or any part of her body, because he has no kinship relationship with her, nor any other cause of mahram status. The mere fact that she is his brother’s wife does not remove her status as a non-mahram to him. Some people have the custom of women uncovering themselves in front of their husbands’ relatives, but this is one of the forbidden bad customs. As for the Shari'ah, it commands hijab (covering) from the husband’s relatives and others. The Prophet (peace and blessings be upon him) was asked about a pregnant woman, who is a relative of the husband, and he said, “A pregnant woman is death,” meaning that the danger is greater and the precaution required is stricter.