Answered by Shaykh Abul ‘Ataa Ahmad Banaja (may Allah preserve him)
If someone owes a debt to someone but that person or people aren’t available or can’t be contacted, then is it permissible to give the debt money to charity?
And if so, then can you give the debt money to those who you’re obliged to spend on? Like grandmother, mother, father etc.?
My dear brother, no, you are absolutely not allowed to spend the money that you took it from someone as a debt, in something other than to pay him back or paying for something for him, with his own permission. If you couldn’t find him, you must understand, it will remain as a debt on you even if you pay it for the sake of anything, until you meet him. If he passes away, you give (it to) those people who inherit from him. You give it to those who inherit from him, and you tell them that it’s a debt from his father or their brother or their son etc. It will remain with you die 100 percent. The difference is, if you really have the intention to pay it back, but you couldn’t find him, May Allah excuse you. And if you don’t have the intention, to pay him at all, it will remain in your name, until you meet Allah Ta’aala.
In the end my dear brother, you don’t have the choice to spend on anything other than by his own permission. Otherwise it will remain as a debt on you until you meet him or you die or you meet Allah Ta’aala and he forgive you, because you had the intention to pay him but you couldn’t find him.
“لَا یُكَلِّفُ ٱللَّهُ نَفۡسًا إِلَّا وُسۡعَهَاۚ”
“Allah does not charge a soul except [with that within] its capacity.” [Surah Al-Baqarah 286] It doesn’t matter whether the amount is small or big, it doesn’t matter if it was material or a liquid cash or whatever. BaarakAllah Feek.