Adult brothers and sisters sharing the same room in Islam

Islamic guidelines recognize the concept of khalwa, which permits a woman to be in seclusion (alone in the same room or dwelling) with her male mahram. This crucial exception to the general Islamic principle of avoiding seclusion with non-mahrams stems from the profound trust and familial bond inherent in the mahram relationship.

A mahram is a male relative with whom marriage is permanently prohibited due to blood relations (such as father, brother, uncle) or marriage relations (such as father-in-law, step-father). This prohibition of marriage signifies a sacred and inviolable bond, establishing a level of trust and intimacy that transcends typical social boundaries.

The allowance for khalwa with a mahram underscores the Islamic emphasis on preserving familial honor and safeguarding women's dignity. By recognizing the mahram relationship as a safe and trusted environment, Islamic guidelines acknowledge the inherent purity and respect within such familial bonds. This principle of khalwa extends even to mahrams whom the woman has never met before. For instance, if a woman's long-lost brother is suddenly discovered, or if she marries a man whose father she has never encountered, the mahram relationship is immediately established, and the allowance for khalwa applies. In all these cases, the trust and sanctity of the mahram relationship are upheld, regardless of prior acquaintance.

Therefore, a woman can dwell permanently in the same room with her brother, for example, due to a lack of available space. Similarly, temporary seclusion, such as sharing a hotel room with a mahram during travel, is also permissible.

Furthermore, a woman may even share the same bed or sleeping mat with her male mahram, provided that they refrain from sleeping under the same cover and diligently maintain the proper covering of their awrah (the area of the body extending from the navel to the knees).

A significant aspect of this allowance pertains to the woman's dress code within the confines of this trusted space. While Islamic guidelines generally emphasize modesty in public settings, the dynamics within the mahram relationship allow for greater comfort and relaxation within the shared space. Specifically, a woman is only obliged to cover her body from the navel to the knees in front of her male mahram. This means that within the room they share, she can wear comfortable and practical clothing without the need for the additional layers or coverings often required in public. For example, she could wear a knee-length or ankle-length shirt, a comfortable house dress, or similar attire without feeling obligated to wear a dupatta, scarf, trousers, or other outer garments that might typically be worn in the presence of non-mahram men. This allowance recognizes the inherent safety and trust within the mahram relationship, allowing for a more relaxed and natural environment within the shared living space. This also takes into account the practicalities of shared living, especially in situations where a woman might be living with a male mahram due to limited space or during travel, where comfort and ease of movement are important considerations. 

This freedom extends to the shared use of facilities and belongings within their shared living space. They are permitted to share the bathroom and toilet attached to that room, facilitating convenience and practicality in their daily routines. Furthermore, the sharing extends to common amenities and furniture within the room. They can share the same closet, allowing for efficient storage of their belongings. They may also share a dressing table, facilitating shared use of mirrors and grooming items.