Matt had to cut what was used in the script in this issue down because it wouldn't fit on the page, but below are the Latin and english versions of a Catholic Last rite in its entirety. This is actually from a Raccolta written in 1923, but it is based on an oral tradition that dates back to the Dark Ages-which is why he used it.
Gloria Patri, et Filio, et Spiritui Sancto. Sicut erat in principio, et nunc, et semper, et in saecula saeculorum. Amen.
Glory be to the Father, to the Son, and to the Holy Ghost. As it was in the beginning, is now, and ever. Amen.
INCLINA, Domine, aurem tuam adpreces nostras, quibis misericordiam tuam supplices deprecamur, ut animam famuli tui Percival, quam de hoc saeculo magrare iussisti, in pacis ac lucis regione constituas et Sanctorum tuorum iubeas esse consortem. Per Christum Dominum nostrum. Amen.
INCLINE Thine ear, O Lord, unto our prayers, wherein we humbly pray Thee to show Thy mercy upon the soul of Thy servant Percival, whom Thou hast commanded to pass out of this world, that Thou wouldst place him in the region of peace and light, and bid him be a partaker with Thy Saints. Through Christ our Lord. Amen.
Taken from Lady Pendragon Vol.3, #5