Excerpt from Mr. Adnan Oktar's Live Conversation on A9TV dated October 11th, 2017

VTR: Surah Ya Sin is sent down for the living, why is it read after the dead?

ADNAN OKTAR: Such a handsome young man, may God prolong your life. May God show you the right path. It's good to read from the Quran by one's grave. God is being remembered, it brings relief to one's heart. It does no good to the dead though. If he was a cruel person there is no benefit for him in that; but if he was a good person, and raised good children and their children are reading the Quran, it is good.  However, let me say that if  the person who recites the Quran thinking that the the dead will hear, it is actually idolatry. Clearly, the dead will not hear him. God says "they will no longer hear you, their connection to this world is severed." Despite what is said in the verse if you still believe that the dead can hear you, it means you are claiming he is "not dead" while God says he is. God says "they will never return to the world again", and you ask "why wouldn't he? Here he is." That is wrong. But if one reads from the Quran to make it heard by the people around, to spread the word of God, it is a good practice. It doesn't have to be Surah Ya Sin specifically, any verse from the Quran can be recited.