Praise be to Allah.
appreciate your good deeds and upholding the ties of kinship and helping
your relatives financially. We ask Allaah to reward you with good.
It is permissible for a person to borrow money in order to do Hajj, if he is confident of his ability to repay, such as if he is employed and has a regular income, and he knows that his salary will be enough to pay off the loan, or if he has a business and so on.
It says in Mawaahib al-Jaleel (2/531):
In the Mansik of Ibn Jamaa’ah al-Kabeer it says: if he borrows permissible money to do Hajj and he is able to repay it and the lender agrees, there is nothing wrong with that. End quote.
This was also stated in fatwas issued by the Standing Committee and Shaykh Ibn Baaz (may Allaah have mercy on him).
See: Fataawa al-Lajnah al-Daa’imah (11/41) and Fataawa al-Shaykh Ibn Baaz (16/393).
If you do that, then you will have combined all interests: you will have done Hajj and you will have treated your brother well, and you will have fulfilled your promise.
If you cannot find anyone to lend you money, then you should look to see which interest is more important, and give priority to that one. You should also give priority to the interest which cannot be delayed over that which can be delayed.
Think about Hajj: is it obligatory for you? Or have you already done the obligatory Hajj, and you want to do a naafil Hajj?
Look at your brother’s needs: is it an urgent need or not? Can you delay it for a month or two, or not? Can you lend him some of what he needs now and delay the rest, or not? … and so on.
We ask Allaah to help you to do what which is best.
And Allaah knows best.