Dr. Marawan Shahin, Professor of Hadith and its Sciences, Faculty of Usul Ad-Din (Theology),Al-Azhar Univ. states: “Gathering on Thursday night after Maghrib Prayer to read surat Yaseen, as far as I know, there is no evidence proving it. However, generally speaking, we must point out that specifying certain times for certain acts of worship needs an evidence. So, if they do so without believing that it is part of the Sunnah to do so in that specific time, there is nothing wrong with it.

As for the issue of reciting surat Al-Kahf on Thursday night, we’d like to state that Abu Sa`id A-Khudri (may Allah be pleased with him) said: “Whoever reads surat Al-Kahf on the night of Friday, will have a light that will stretch between him and the Ancient House (i.e., the Ka`bah).” (Reported by Al-Darimi)

Ibn `Umar (may Allah be pleased with him) quoted the Prophet (peace and blessings be upon him) as saying: “Whoever reads surat Al-Kahf on the day of Jumu`ah (Friday), a light will shine for him from beneath his feet to the clouds of the sky, which will shine for him on the Day of Resurrection, and he will be forgiven (his sins) between the two Fridays.”
hence, one may read surat Al-Kahf during the night or the day of Jumu`ah. The night of Jumu`ah starts from sunset on Thursday, and the day of Jumu`ah ends at sunset. Therefore the time for reading this surah extends from sunset on Thursday to sunset on Friday.

As for the issue of denoting the reward of reciting the Qur’an for the dead, it is a controversial issue among Muslim scholars. For sure there is a reward for reciting the Qur’an but there is no evidence stating that the Prophet (peace and blessings be upon him) recited the Qur’an and gifted its reward for a dead. There is no clear evidence that the Prophet (peace and blessings be upon him) did or commanded this to be done.

However, he is reported to have advised Muslims to ask Allah for forgiveness on behalf of a dead. Another group of Muslim scholars are of the opinion that the reward of reciting reaches the deceased. He/she (the dead) also benefits from the du`a’ (supplication), charity or Hajj done on his/her behalf.