All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If your brother pays the expenses of your Hajj on your behalf then your Hajj is correct and valid, whether it is an obligatory or supererogatory Hajj. Performing Hajj only using one's own money is not a condition for the validity of Hajj.
However, spending one's own money to perform Hajj is preferable and greater in reward.
The important condition is that Hajj should be performed only with lawful money.
Allah knows best.