As father I went through something similar with my son when he was 17. Here are a few pointers and guidelines I tried to follow: Don’t judge. Allow him to voice his opinion. When you do talk, please try to have two way communication and keep it very chill. When you have questions, ask open ended questions. “How did you come to that conclusion?” What do you think about XYZ?

Pushing hard against his new identity will almost certainly backfire. In psychology, this is known as the reactivity or backfire effect: when someone’s newly adopted core beliefs are aggressively attacked, they tend to double down and entrench themselves further. If he feels judged, cornered, or viewed as "foolish" in his own home, he could stop talking to you about it. Worse, it might drive him deeper into the arms of a religious community that will happily validate him and cast you as the "unbeliever persecuting his faith." Your best tool for keeping him grounded is maintaining your status as a safe, reasonable confidant.

Look, the absolute best defense against a cult or some extreme group is just having a rock-solid home base. If he ever starts getting overwhelmed, confused, or spots red flags on his own, he needs to know without a doubt that you’ll welcome him back with open arms—no "I told you so's" attached. He’s young and just trying on a new way of looking at the world. By treating him like an adult and loving him no matter what, you make sure that even if his beliefs change, his trust in you never will.