ANSWER:
You must hold your ground and tell him that if he does it outside the house, he is the one responsible and he will be punished for that in hell but not you are parents, as you are obliged to prevent him from such haram.
ANSWER:
You must hold your ground and tell him that if he does it outside the house, he is the one responsible and he will be punished for that in hell but not you are parents, as you are obliged to prevent him from such haram.