Is it permissible to give a poor brother from Zakat funds to help him complete the construction of his modest house on land that he does not own, knowing that he has already been given an advance amount from Zakat?

Zakat is only to be given to the eight categories [of recipients]. It is permissible to give it to your brother for building a house if he is poor (miskin) or needy (faqir), does not own another dwelling, and is unable to secure one even through affordable rent. It is also permissible to give him Zakat to pay off his debt to your father if he is unable to repay it, considering him to be among the debtors (gharimin). What you have given him previously is sufficient if he was poor (faqir) or needy (miskin); otherwise, you must pay Zakat again.