How do parents feel when their children reject the values and/or religious faith of the parents? It can be a delicate question, or it can be a "Hey, they're grownups now. They make their choices."
Or the parents may moan and wonder where they went wrong. Or they may be angry, and their questions may be aimed at the offspring. "How can you do this?" Sometimes it's "how can you do this to us?" and sometimes it's "how can you do this to yourselves, and your children?"
I don't have an answer that suits everybody in this situation. I'm not sure I have the answer for me. But I'm from the 'I do the best I can and leave the rest up to God' contingent. My faith is of the kind that believes that we try to control our lives, and the lives of others, much too often. Not always with any success, I might add. If we plan, maneuver, capitulate, demand or beg, we might depriving our children of experiences that God can use to convince them of His presence.
And in the meantime, we can show patience and trust, two very handy attributes for our children to acquire, as well.