About him: https://www.franciscanmedia.org/saint-louis-of-france/ 

Prayer for families,in union with St. Louis, virtuous father of 11 children.

O Lord, God of goodness and mercy,
Who in the midst of an evil and sinful world
hast presented to the society of the redeemed
the Holy Family of Nazareth
as a spotless mirror of piety, justice and love,
behold how the family is being undermined on all sides,
every effort being made to desecrate it
by stripping it of faith, religion and morals.

Regard the work of Thy own hands.
Safeguard in our homes the domestic virtues,
for these alone will ensure us harmony and peace.

Come and stir up the champions of the family.
Bestir the modern apostles so that in Thy Name,
bearing the message of Jesus Christ
and exhibiting holiness of life,
they may revive the doctrines of conjugal fidelity for married couples,
the exercise of authority by parents,
obedience on the part of children
and modesty on the part of girls.
Grant also through the efforts of these apostles,
that the home favoured by Thee with many blessings
may again become an object of esteem and love
in the minds and hearts of all.

It is through the examples of the Divine model of Nazareth
that the Christian family is to be restored in Jesus Christ
and to recover its former respect and dignity.
Then every home will again become a sanctuary
and in every household will be rekindled the flame of faith
to teach patience in adversity
and moderation in prosperity
and to promote order, peace and harmony in all things.

Under Thy paternal gaze, O Lord,
and with confidence in Thy Providence
and in the loving patronage of Jesus, Mary and Joseph,
the family will become a sanctuary of virtue
and a school of wisdom.
It shall prove, as Christ has promised,
a haven of rest against life's burdens.
In the sight of the world it shall render glory to Thee, O Father,
and to Thy Son, Jesus, until the day when,
through Him, we shall, together with all His members,
sing the Divine praises in the eternal ages to come.

Amen.

(By Pope Pius XII) 

Reproduced from https://www.catholic.org/prayers/prayer.php?p=565