Every so often a reader writes me about a grown child who has left the Catholic faith. Invariably the worried parent longs for an answer to the big question. How can I draw this person back to the Catholic Church? Often hidden in these lines is an underlying worry: Did I do anything wrong?

I’m not a parent so I always start with that disclaimer, but I do have nieces, nephews and godchildren so it’s not like I’m living in a cave when it comes to families. Also, I left Catholicism behind in college, and didn’t return until my forties.

My own Catholic parents were spared the suffering of knowing their daughter had left the faith since I was skilled at covering my tracks. But many adult children are more open about their decisions, and their parents sometimes ask me, “What should I say? What books should I recommend?”

Sadly, there is no book you can hand someone that will magically bring them back into the Catholic fold. As for me, I had a book on my shelves for many years but never opened it. Then one day something prompted me to pick up Thomas Merton’s “Seven Storey Mountain” and start reading it.

What drew me in was Merton’s striking honesty about the years when he was searching for happiness in all the wrong places, and his remarkable change of heart later. To say that I identified with him would be an understatement.

Still, I could hand this tome to a nonbeliever today and they might never open it. It clearly took an outpouring of God’s grace to spur me to plumb its depths.

God stands at the heart knocking, but we decide whether or not to welcome him. Some parents, however, are so impatient for the child to open the door that they get tied up in emotional knots.

“How many people lose their peace because they want … to change those around them,” writes Father Jacques Philippe in his book “Searching for and Maintaining Peace.”

Peace of mind comes from understanding that fallen-away Catholics often have deep emotional wounds. In my case I had become ensnared by the treacherous trap of secularism that still lures many college students away from God. I was angry at God for all the suffering in the world, and later, when my parents died, I blamed him for their deaths.

When your child was young and skinned her knee, you could come running with Band-Aids and iodine, but there is no easy fix for a grown child with a hidden hurt.

In 1942 British author Caryll Houselander, who had left the fold and returned, suggested that if fallen-away Catholics encountered more sympathy and love, they would always come back. As she put it, the Church is their home, and leaving it means being “endlessly homesick.”

I always advise parents to pray, have Masses celebrated and offer up their Holy Communion for the child. I also remind them about a distraught woman long ago who prayed fervently and fasted for an adult son who rejected Christianity and was living with his mistress.

One bishop whom this mother implored for help assured her, “It is not possible that the son of so many tears should perish.” It took nine years to prove the clergyman right, but the son eventually converted, going on to become a priest and then a bishop himself.

Yes, that son was St. Augustine and the mother was St. Monica—and she is a good intercessor for parents worried about their children. But St. Monica did more than fast and pray. She also courageously told her son in no uncertain terms that his immortal soul was in danger because of his lifestyle.

It is also important to do the hardest thing of all, which is to surrender your beloved into the hands of God and recognize that the Good Shepherd is eager for his prodigal children to return to him.

I can also imagine St. Monica telling you: “Remain steadfast in your love! Continue seeing Christ in this wayward child.” And she might add, “Most of all, pray that your son or daughter will look into your eyes and behold Christ reflected there too.”