Answered by: Imam Abdul-Malik Sheikh
Does a woman have to wear Hijab in front of the husband of her auntie (her father’s sister)?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
A woman has to observe Hijāb (Purdah) in front of all non-Mahrām males. A Mahram is with whom marriage is never permitted to marry because of their due to kinship, foster relationship, or relationship by marriage.
The husband of a woman’s aunt is not her Mahram, i.e. he is not one of those with who marriage is permanently unlawful. Therefore, she is required to wear Hijāb in front of her aunt’s husband.
Only Allah knows best
Written by Imam Abdul-Malik Sheikh
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Badai al-Sana’i Fi Tartīb al-Shara’i vol. 2 p.256