Why would anyone commit their soul to an organization?
As you said your friend was feeling very vulnerable when he joined and in need of friends. Now he's been taught that if he leaves he could face eternal destruction.
What really hit me is that people say the JW organization is a cult and that their members are brainwashed. Then I started to remember little things that happened in our relationship that pointed to his odd behavior.....Is he always going to be so conflicted and give up things that make him happy?
Yes I'm afraid he is going to be forced to give up things that make him happy. I know you want to help him and this situation is awful for you but there's no way he didn't know dating outside the religion is discouraged and sex before marriage is strictly forbidden. I'm not going to tell you what to do. I hope your young life won't be blighted by this cult. Good luck xx