Though it is not only saint Benedict whom we can pray for a happy death, saints like Joseph, the father parent of Jesus can be also our recourse. But let me put here also the prayer for saint Benedict for happy death.
"O holy Father, St. Benedict, blessed by God both in grace and in name, who, while standing in prayer, with hands raised to heaven, didst most happily yield thy angelic spirit into the hands of thy Creator, and hast promised zealously to defend against all the snares of the enemy in the last struggle of death, those who shall daily remind thee of thy glorious departure and heavenly joys; protect me, I beseech thee, O glorious Father, this day and every day, by thy holy blessings, that I may never be separated from our dear Lord, from the society of thyself, and of all the blessed. Through the same Christ our Lord. Amen."