Is the wife wrong to object to her husband spending on his well-off brother and his family, while she sacrifices her basic rights to housing and gold? And does this please Allah?

The wife erred by denying her husband's spending on his family, because the money is his private right to spend as he wishes, subject to two conditions: that it be spent on permissible things, and that it not violate the rights of the wife and children. As long as the husband has provided a dwelling and gold, and fulfilled his duties towards his wife regarding food, clothing, and medical treatment, there is no blame upon him for what he spent thereafter, and the wife has no right to object. A husband's spending on his family is among the great acts of worship for which he will be rewarded, and it is not an injustice to himself or to his wife.

As for the wife's relinquishment of the dowry: if it was before the marriage contract, it is void, and she has the right to demand it. If it was after the marriage contract, it is a valid relinquishment that cannot be retracted except by a gift from the husband. The wife is entitled to a dowry equivalent to that of her peers, even if she relinquished it before the contract.

Advice for the wife: Fear Allah, and be keen on obeying her husband and pleasing him in what is good, for this is one of the greatest reasons for Allah's pleasure and entering Paradise. Indeed, a husband's kindness to his family brings blessings and abundant provision in this world and the Hereafter.