Is a close relative who is in debt, having bought a house and having a car loan, and whose salary is 7,000, considered eligible for zakat?

The recipients of Zakat are eight categories, as mentioned in the noble verse. Among them is the needy (al-miskin), who is one who does not find what suffices his basic needs. Your brother is eligible for Zakat if he is poor or needy, or if he is in debt and unable to repay it. Giving Zakat to a relative (if he is eligible) is better, as it combines charity with upholding kinship ties.