Charity requires us to pray for the dead. In the case of our parents, to do so should not be simply a duty but a joy. They gave us life and brought us up in the Faith; we should be happy that our prayers can help end their sufferings in Purgatory and bring them fully into the light of Heaven.
This prayer is a good way to remember our parents, who have gone before us. It is especially useful to pray as a novena on the anniversaries of their deaths; or during the month of November, which the Church sets aside for prayer for the dead; or simply anytime that their memory comes to mind.
A Prayer for Deceased Parents
O God, who hast commanded us to honor our father and our mother; in Thy mercy have pity on the souls of my father and mother, and forgive them their trespasses; and make me to see them again in the joy of everlasting brightness. Through Christ our Lord. Amen.