Even though the basic principle is that a person should pay for his own Hajj if he is able to, performing Hajj with the brother’s money is valid. The person who does this will not be required to perform Hajj again out of his own money.

Dr. Muzammil H. Siddiqi, president of the Fiqh Council of North America, stated,

If the Hajj was performed at a young age, then the person must perform the fard (obligatory) Hajj when they are able to do so.

However, if the Hajj was performed at a later age, then he/she has fulfilled the obligatory Hajj.
It goes without saying that this person can still perform voluntary Hajj.