Answered by Ustadh Salman Younas
Question: I have always considered my sister’s husband my non mahram and I have always covered in front of him. However my friends claim othewise.
I am very confused. What is the truth about this issue?
Answer: wa `alaykum assalam
Your sister’s husband is a non-mahram to you. Therefore, you are obliged to cover in front of him. I do not know of any difference of opinion on this issue amongst the scholars.
As for the line of reasoning being employed to state otherwise, it is not sound since the general definition of a ‘mahram’ is one with whom marriage is permanently unlawful.
For further details, please refer to: Who is Mahram
Checked & Approved by Shaykh Faraz Rabbani.