What is the ruling on speaking about a brother's wife who takes money and spends it on her family, with or without her husband's knowledge, and what should the sister do to make her parents aware that what her brother's wife is doing cannot be condoned, knowing that this matter causes psychological distress to her parents because the couple has not built their future despite many years of living abroad?

It is permissible for a wife to dispose of her husband's money with his knowledge, as long as it is not extravagant. She is praised for this if it is for her parents' piety and maintaining ties of kinship. However, without his knowledge, it is not permissible unless it is a small amount that people commonly overlook, or if she knows he would approve. This is based on the Prophet's (peace and blessings be upon him) saying: "If a woman spends from her husband's house without causing ruin, she will have her reward, and he will have a similar reward for what he earned." If she disposes of it without his consent or is extravagant, that is a reprehensible act that should be addressed by advising her. If she does not respond, the husband should be advised on the matter because he is the owner of the money, while ensuring that this does not lead to a greater reprehensible act such as severing kinship ties or causing discord.