What should I do about my supplication (du‘aa’), as I asked Allah to take from my lifespan and add it to my friend’s lifespan?

He prays for his Muslim brother in his absence, then tells him about that

The supplication of the Muslim is answered by granting him what he seeks or otherwise

Why does Islam urge us to offer supplication, when Allah, may He be exalted, may not respond to the one who calls upon Him?

Du`a for something the outcome of which has already been determined

causes of apathy and the remedy for that

Du‘aa’ of the Sahaabah at the beginning of the month

Ruling on a person saying “O wisdom of Allah” or “O mercy of Allah”