Praise be to Allah.
Distributing tapes which contain lessons, lectures and guidance is a means of giving charity on behalf of the deceased, if it is intended that the reward should go to him. This is one of the best things that the living can do for the dead, and this is confirmed in the shar’i texts which indicate that the reward will reach the one on whose behalf charity is given.
It was narrated from ‘Aa’ishah (may Allaah be pleased with her) that a man said to the Prophet (peace and blessings of Allaah be upon him): My mother died suddenly and I think that if she could have spoken she would have given charity; will she have a reward if I give charity on her behalf? He said: “Yes.” Narrated by al-Bukhaari (1388) and Muslim (1004).
Imam al-Shaafa’i (may Allaah have mercy on him) said in al-Umm (4/126):
The dead may benefit from the actions of another in three cases: Hajj performed on his behalf, wealth that is given in charity on his behalf, and du’aa’. … And Allaah is most generous because He will reward the living and benefit the dead.
Al-Nawawi narrated in al-Majmoo’ (5/293) that the Muslims were unanimously agreed that charity on behalf of the deceased benefits him and reaches him.
Ibn Taymiyah said in al-Fataawa al-Kubra (3/29):
The imams are agreed that charity reaches the deceased, as do other financial acts of worship such as freeing slaves. End quote.
Ibn Hajar al-Haytami said in Tuhfat al-Muhtaaj (7/72-73):
The deceased is benefited by charity given on his behalf, such as donating Mus-hafs as a waqf and so on.
See also the answer to question no. 42384.
There is nothing wrong with distributing these tapes as an act of charity on behalf of the deceased during the condolence gathering or afterwards, but that is subject to the condition that you do not believe that giving charity during the days of mourning is of extra virtue, as some people think that giving charity during the mourning period is essential to help the deceased in the initial period in the grave or make him happy in his grave and other such false beliefs.
And Allaah knows best.