Is it permissible for a man to enter upon his wife's mother and sister while they are alone in their home? Noting that he sits in the living room while his wife's sister is in her room and does not come out and he does not go into other parts of the house.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

It is permissible for a man to enter upon his wife's mother, shake hands with her and meet her in private when there is no temptation, since she is a Mahram to him. He is not permitted to do so with his wife's sister unless she is his suckling sister. Nevertheless, he is permitted to enter upon her in the presence of someone – such as his wife's mother – as long as a meeting of a couple in private does not occur.

Consequently, it is permissible for such a man to enter upon his wife's mother and sister in the way he referred to in the question while they are alone in their home.

Allaah Knows best.