Encouraging children right from their youth to make reparation to Jesus and Mary, out of love for God, and to offer up acts of reparation on behalf of their friends, out of love for neighbor, is among the best and most profitable things that cane be done for their soul imho. What St. Montfort says about total consecration may be helpful to understand how what we offer for others can be beneficial for them; if we offer Our Lord or Our Lady all the fruits of our works, or some particular work, that they may be applied to others, Our Lady will take the satisfactory value of those prayers and sacrifices and apply it to gaining graces for them. The more devotion and love with which we complete the task prescribed, the more efficacious grace we will draw down on them. It's up to us if we want to do so or not. This is the great double Novena, of 9 First Fridays and 9 First Saturdays together, approved by the Church, where the Lord Himself explained the principle that Parents especially can help ensure the salvation of their children, by making this 9 month novena for them: "If parents or other members of a family make this novena, no member of that family will be condemned to Hell." The same principle applies to offering it for one's other family members and friends, "The sinners will be converted without difficulty, even though somebody else makes this novena for them." Please see:
http://lapieta.tripod.com/dnov_ena.html This revelation is judged worthy of credence by the Church and you'll find it in old prayer books. Also found on this site: https://sites.google.com/site/doublegreatnovena/the-33-promises