A lady who is living happily with her husband in a Western country and his sister decided to move with them from her original country. She's not married; her mom is alive her dad is dead. She has a good job, and can afford to live on her own next to her brother rather than with him in the same place. Then conflicts with the wife will be avoided for everybody will have space of freedom in her house. Should the brother keep his sister in his place, knowing that it's not that big and that disagreements between the sister his wife are pretty predictable from previous visits?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

We do not know why this woman does not want to stay with her mother who is still alive. Neither do we know why she is interested in living with her brother in a western country, even though it may cause problems between her and her sister in-law.

However, staying overnight alone is not desirable for men. Ibn Abu Shaybah reported in his Musannaf from ‘Ataa’ that the Prophet forbade traveling alone or staying overnight alone. (This is a Mursal Hadeeth).

Abu Ja’far, another narrator, reported the narration with the following wording: “Do not spend a night alone in a house because Satan will be very fond of you.”

‘Umar said: “No one should travel alone, and no one should spend the night alone.” [Al-Albaani: Sound]

Therefore, if staying alone is not desirable for men then it becomes more emphatic for women. However, staying alone overnight is not forbidden if it does not lead to any temptation or bad consequences.

Moreover, if her stay with her brother causes any harm to him or to his wife, then she is not permitted to live there. The Prophet said: “There should be no harm, nor reciprocal harming.” [Ibn Maajah]

If there is no harm, then she can live with them.

Allah knows best.