Is zakat obligatory on the creditor for the money he lent to his brother for 19 years, and how is it calculated?

First: The zakat on debts depends on the debtor's situation: 1. If the debtor is solvent (able to pay): Zakat is obligatory upon the creditor every time a year passes (hawl), even if the debt remains for years, provided the wealth reaches the nisab (threshold). 2. If the debtor is insolvent or procrastinating: Zakat is not obligatory until the debt is collected and a year has passed over it (according to the Hanafī school), or the creditor pays zakat on it for one year after collecting it (according to the Malikī school).

Second: As long as the creditor's intention has not definitively waived the debt, the debt remains, and the aforementioned zakat rulings apply to it based on the debtor's solvency or insolvency each year.

Third: In the event that zakat is obligatory, the creditor endeavors to estimate the amount due for zakat for each year and pays 2.5% of it, as long as the wealth has not fallen below the nisab.