This is because Yan respects Buddhism very much!
When ordinary people were alive, they didn't do many good deeds and merits, but they did a lot of evil. So he failed to ascend to heaven after death, but went to hell to be judged by the king of hell. Living family members can recite Buddhist scriptures for the deceased or ask monks who are clean and disciplined to recite scriptures for the deceased, so that the deceased can get merits. Because Buddhist scriptures have the merits of Buddha and Bodhisattva, which can purify the soul, chanting scriptures is a great merit! So the dead can live beyond life.
Besides, Buddhist scriptures are not just for the dead. Living people chanting Buddhist scriptures will increase happiness and longevity!