Yes, your serious problem is weakness. Easy for a non-jw to say, but that's what it boils down to, nothing else. Your wife and everyone else are going to walk all over you because you let them.
When I learned TTATT, I immediately told my wife how I felt about it, pulled my son out of preaching and theocratic school and allowed him only the weekend meeting. Ever since I asked my son to read Crisis of Conscience, now he is reading Carl Olof Jonsson's Signs of the Last Days. Next it will be The Gentile Times Reconsidered. He knows he is not allowed to preach or attend the Theocratic School or get baptized for as long as he lives under my roof. Many here have criticized my tactics, but I am taking definitive actions and I am showing my resolve about something that I am passionate about: protecting the mental well being of the young.
It seems that you care more about other's approval than you care about the well being of your son. It's a damaging cult, especially damaging to the young. Are you worried about being disfellowshipped? So be it. It's a bit too late to be concerned about that. It may even be a good thing because then you can help your son without the restrictions imposed by the cult.