Does donating a sum of money, borrowed on behalf of its owner whose whereabouts are unknown, count as repayment of the debt?

The fundamental principle in fulfilling rights and debts is to give them to their rightful owners. The Prophet, peace and blessings be upon him, emphasized this greatly, for rights will be settled on the Day of Judgment. Even a martyr will be withheld from Paradise due to debt. Therefore, the questioner must exert every effort to pay off his debt. If he is unable to do so, then he should give charity on behalf of the owner of the money so that the reward of the charity reaches him. If the owner of the money approves it, then that is good. Otherwise, his right must be paid to him, and the reward for the charity will be for the one who gave it.