Is the wife sinful for her husband's brothers remaining in the house despite the immodesty of one of them and despite repeatedly advising the husband to no avail?

The husband's guardianship of his sisters is obligatory, and he should be moderate in this, so that their rights do not override the wife's rights, or vice versa. The presence of the husband's elder brother in the house, without him adhering to Islamic manners, is not permissible, especially if it leads to unlawful seclusion (khalwa) or the exposure of 'awrah. The husband must advise his brother about this. The wife should be patient and present her words to her husband well, and strive to cover herself when the husband's brother is present.