It's unfair to punish someone for typical feelings. It really takes a special kind of robot to be a perfect JW.
Please encourage him to go to college and, if possible, as far away from his parents as he can get. I'm sure he feels trapped. He's been a good boy all his life and done everything his parents and his God want. And now, for having a natural connection to a pretty girl, all of his accomplishments are being thrown out and forgotten. Get this guy out of there.
What is more is, I'm sure his father is being so extreme because he wants to protect his own position as an elder in the congregation. He'll hang his son out to dry just so he can show the rest of the congregation that he's a super awesome JW.
When pieces of trash manipulators who are lead by feelings of jealousy have more power in the congregation than good and decent human beings you know there's nothing divine there.