Agreed, but just to expand on your point - he’s almost 18 and able to make his own choices soon. If he chooses to leave the church his entire immediate family disowns him, that’s for certain. That’s what they do. If he isn’t drinking the kool-aid, having someone there to help could make a huge difference in which direction his life goes.
My sister dated an ex JW at around 18. He stayed on our couch for a few weeks after his family disowned him.
Knowing Better is such a fantastic youtube channel. I can’t recall this video specifically but ALL of his videos are worth the hour long watch.