Who is more entitled to collect the rent for the apartment agreed upon for purchase between the husband and his brother, given that the husband has not yet taken possession of the apartment, and his brother has rented it out and kept the rent for himself? And is the wife justified in seeking divorce from her husband due to his breach of agreement and his disregard for her?

Selling an apartment on the condition that the seller benefits from it until the end of Ramadan (definition) is valid, and the seller has the right to rent it out during this period, and the rent belongs to him. A husband giving his wife's money to his brother without her consent is wrong, but it does not justify demanding a divorce or intense dispute. The wife should treat her husband kindly and try to reach an understanding with him.