Ruling on a woman uncovering herself before her husband's brother, her uncle, and her maternal uncle

Question:
Please inform us about a woman uncovering herself before her husband's brother, as well as the wife of the uncle, and the maternal uncle. May Allah reward you with the best reward?

Answer:
The paternal uncle, the maternal uncle, and the husband's brother are all not mahram (relatives one may not marry), so she is not permitted to uncover herself before her husband's brother, nor before her husband's paternal uncle, nor before her husband's maternal uncle; because they are not mahram.
The only mahram are the husband's father, the husband's son, and the son of his son. His children and his fathers are the mahram. So she is permitted to uncover herself before her husband's father, and before her husband's son. She is also permitted to uncover herself before her husband's sons, her husband's grandsons, and her husband's granddaughters; because they are his children. As He (Exalted and Majestic is He) said: [Surat al-Nur: 31]. The "bu'ul" (husbands) are the spouses.
As for the brothers, the husband's brothers, his maternal uncles, and his paternal uncles, they are not mahram. It is not permissible to uncover oneself before them, nor to be in seclusion with any of them.