The ruling on the husband's maternal uncle seeing his wife and a clarification of the mahram relatives

Question:
Praise be to Allah, and may peace and blessings be upon the Messenger of Allah, and upon his family and his companions, and those who follow them. May Allah reward you, Honorable Shaykh, and may Allah bless you, and may He reward you with the best reward for the Muslims. The questioner says: I have a maternal uncle who is my mother's brother, and I am engaged to a woman who wears the niqab. I did not let him see her, but he became angry with me. Is it permissible for him to see her, even just once? And who are the mahram relatives for my wife? Please give us a ruling, and may you be rewarded, and may Allah reward you with good.

Answer:
It is not permissible for your maternal uncle to see your wife, meaning that she should not uncover her face for him and he should not look at her, because he is a non-mahram to her and not a mahram. The only ones for whom it is permissible for your wife to uncover her hijab are those whom Allah mentioned, who do not display their adornment except to their husbands, meaning the spouses, . , so the one for whom it is permissible for your wife to be seen, and who is a mahram to her, is your father or your grandfather, he is your father or your grandfather, or your son or your son's son, and so on down the line. These are the ones for whom it is permissible for your wife, meaning your son from another woman, your son from another woman, is a mahram to her, so it is permissible for him to see her and to travel with her. Except to their husbands, or their fathers, or the fathers of their husbands, meaning the fathers of the spouses, or their sons, or the sons of their husbands, meaning the sons of their spouses from other wives. They are mahrams to his wife. As for your maternal uncle, he is not a mahram to her. Your brother, your brother is closer than your maternal uncle, your brother is closer than your maternal uncle, and yet it is not permissible for him to see your wife. Yes.