Should I postpone Hajj until next year, or fulfill my promise to my needy brother, or perform Hajj with the money I allocated for him?

It is permissible to borrow money for Hajj if the person is confident in their ability to repay, such as an employee who has a salary sufficient to cover the debt, or a merchant. If he cannot find someone to lend him money, then he must balance the interests and prioritize what is more important. He should consider the obligation of Hajj and the need of his brother, and whether it can be postponed or partially fulfilled.