Is it permissible for brothers and the father to collect Zakat money to support their brother in his studies abroad, and is it permissible to pay off his debt with this money after he has become a scholarship student?

We have previously explained the conditions for the permissibility of giving zakat to a student of knowledge. If these conditions are met, then he is among those eligible to receive zakat; otherwise, the obligation is not fulfilled. As for what was given as a loan, there is no issue in its permissibility, and it remains a debt upon him. If he is unable to repay it, it is permissible for him to take from zakat, as he is considered among the debtors (gharimin). There is no harm for you in giving your zakat to him, but it is not permissible to stipulate that this zakat be used to repay the debt.