Answered by: Shaykh Ahmed Bin Mohamed Umarji
It’s necessary to wear a niqab In Front of your brother-in-law?
In the name of Allah, the Most Gracious, the Most Merciful
The brother is a non-mahram. The laws of hijaab will be applicable to a greater extent with the brother-in-law.
There is more potential for sin between the two than others.
The Prophet Muhammad (P.B.U.H) warned against such saying, “The brother in law is death.”1
Only Allah knows best
Written by Shaykh Ahmed Bin Mohamed Umarji
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
1 Sahih al-Bukhari 5232