Catechism of the Catholic Church §1688 — excerpt
The liturgy of the Word during funerals demands very careful preparation because the assembly present for the funeral may include some faithful who rarely attend the liturgy, and friends of the deceased who are not Christians.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: OCF 41