Is the presence of a brother in his brother's home, and his stay with the wife, young children, and maid in the husband's absence, considered an unlawful seclusion (khalwa)?

There is no harm in the husband's brother living in the house if he is trustworthy and his presence does not cause him to see his brother's wife. It is known that the husband's brother is not a mahram to his brother's wife, and it is not permissible for him to be alone with her or for her to reveal any part of her body to him. He is like a stranger (ajnabi), and the temptation from him is greater due to the ease of his entry and exit. For this reason, the Prophet, peace and blessings be upon him, emphasized the danger of the hamu (husband's relative), saying: "The hamu is death." This means that the fear of him is greater, and the temptation from him is more severe due to his ability to reach the woman and be alone with her without objection, unlike a stranger. The hamu here refers to the husband's relatives who are not his fathers or sons, such as his brother, uncle, and nephew, and anyone who is not a mahram. Seclusion (khalwa) is negated by the presence of a maid and children who are aware of their surroundings. The most cautious approach is to avoid every avenue through which Satan can enter, except in cases of necessity.