As many here would tell you, go slowly! If you're really concerned abou their spiritual welfare, I would start by stating something very simply... like, "I heard x, y, z about the WT's association with the UN... have you ever HEARD such a thing?" Posing the question like you can't quite believe it. You'll get your answer quick enough about whether they'll just dismiss it or are really curious and TRULY spiritually concerned. If they dismiss it, I personally would totally drop the subject with them, unless, of course, you want to find yourself in front of a committee. They'll turn you in faster than you can blink because they'll think they're "saving" you. Another thing to think about, on another thread a while back, someone said to why not just let sleeping dogs lie, in a sense. If it's not hurting anyone and you do not want to make waves, you continue to believe as you wish and let them continue to worship as they like.