Is it permissible to pay zakat to the intermediary debtor of my mother to settle his debt, since he has become one of those in severe debt?

A person must fulfill their trust (amanah (definition)). If they use it to meet their needs, they have betrayed the trust. If this person is repentant and regretful, and does not have enough to repay the debt, then it is permissible to give them from Zakat (definition) funds, as they are considered a debtor (gharim (definition)), whether they did so out of ignorance or misinterpretation. However, if they are not repentant, then they should not be given. It is best to give the money directly to them so they can pay their debt. But if there is a fear that they might squander it, then it is permissible to hand the money directly to the creditor with the intention of paying off the debt on their behalf.