Is it permissible to pay the debt of someone unable to repay it from Zakat, without informing him, knowing that I was unaware of the condition requiring his permission?

It is permissible to pay off the debt of a person in debt directly from Zakat funds without his permission, because the last four categories of Zakat recipients, including those in debt (al-gharimun), do not require the transfer of ownership to the beneficiary. Rather, Zakat is expended to fulfill their needs. However, the person in debt must be informed that his debt has been paid off so that he does not remain anxious or pay it again.