If you know your position is righteous, you’ve made your point and your opinion is clear, but your child simply won’t accept it, you may have to let him have his way. Let him suffer the consequences, within reason. That’s still not giving up on him. There’s still hope going on there. Suffering consequences can be convincing where nothing else is.
It was not what you wanted to do and it pains you to know that trouble could have been averted, but he (or she) has insisted on his way. If you don’t give up the effort, the more you try, the more he will fight you. Some will fight to extremes you don’t want to go to, and will not give in to you. Some will become a worse person simply to win, so to give up the fight eliminates the conditions for his unrighteousness to become firmly established.
It is a good outcome if the willful person ends up gaining wisdom from the consequences. It may be accomplished the hard way, but it is a positive result just the same. And may I point out: Good for him for overcoming the odds, even if he created his own odds. I still respect him, maybe more so, because he had to swallow his pride to make a fresh start to live righteously.
May God keep you strong and capable. May he help you be flexible, so that you are what your child needs you to be over time. May you allow God to parent THROUGH you. I pray God protects your child as his life unfolds. May you have the wisdom to let him learn and grow. May his highest potential outlast the difficult, troublesome stages of his life. I pray you are rewarded with a deeply loving relationship with your child in the end — lifelong trust, joy, laughter and love beyond measure.