Should he go for Hajj or fulfil his promise to his brother and give him the money?
Question

                A while ago, my brother asked me for money and I promised that I would give him what I had. Two weeks after that, my maternal uncle got in touch with me and asked me for a loan as well. I gave him the money that he asked for, and I could not refuse him because he did me a favour before. Of course the money that I gave him was part of the money that I had promised to my brother. 

My question is: I had intended to go for Hajj, so what should I do? Can I break my promise to my brother, knowing that he needs it, and go for Hajj with it? Should I give him the money and borrow money for Hajj? Of course that is not permissible. Or should I delay Hajj until next year, if Allaah wills?.
Praise be to Allah.Firstly: 
We 
    appreciate your good deeds and upholding the ties of kinship and helping 
    your relatives financially. We ask Allaah to reward you with good.
    Secondly: 
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. 
Thirdly: 
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.