Luke 15:11 - We are God's child by an act of His grace. (Ephesians 1:5)
Luke 15:12 and 13 - Sometimes young people and adults make bad mistakes and we have to let them do so. We are all created as free moral agents. Teach your children right and put them in the Lord's hands (Proverbs 22:6). Teach them right and then let them go (Ephesians 6:4).
Like 15:14-16 - People need to experience the consequences of bad moral decisions. (II Thessalonians 3:10)