What is the ruling on brothers sitting with their wives in one place during visits while the wives are unveiled, knowing that they are cousins, and is the wife sinful if she refuses her husband's request to sit with them, and how should she act?

It is not permissible for a woman to sit with her husband's brothers because they are non-mahram to her, and it is not lawful for them to look at her, nor is it lawful for her to uncover her face and hands in front of them. In fact, interacting with them poses a greater danger, which is why the Prophet (peace be upon him) warned against them by saying: "Beware of entering upon women." A man said, "O Messenger of Allah, what about the Hamw (male in-law)?" He replied, "The Hamw is death." (Agreed upon). If the husband orders his wife to do so, she is not permitted to obey him, based on the Prophet's (peace be upon him) saying: "Indeed, obedience is only in what is good and permissible."