Bobby,
You can get your full-length copy by just asking the JW to provide it for you. Believe me, he will be THRILLED that you wish to go through one of their publications! The nice thing about it is that it prevents rabbit trails. I mean, after all, you are going through HIS OWN publication, and you just want to do it paragraph by paragraph, not skipping anything (He'll think he died and went to Heaven!).
Keep in mind, do NOT let him know that you are doing research based on an outside website. They consider anything written about Christianity to be from Satan himself, unless of course it is a JW publication. Should you try to introduce outside material, you will either scare him off, or he will not come by without having a District Overseer at his side.
All you want to do during this "Trinity" study is to make a case strong enough to sow some doubt into the faithfulness of the Watchtower Bible and Tract Society, that's it! Not until you've done that will his mind be open enough to consider ANYTHING that you say! It might sound crazy, but believe me, as an insider I can attest to that fact.
Take it slow and just do a good job paragraph by paragraph. Slowly his eyes will become opened to Truth, that is, if you can keep others outside of the debate and encourage him to just stay on track with you. There is a real danger that he might get so frightened that what he has been learning from the WTBTS is not true, that he will run to the arms of his leadership and refuse any more dialogue with you. If they catch wind of it, they will STRONGLY encourage him to break off all contact with you and will label you a "goat-like person", not at all open to the "truth" and therefore, not just a waste of time, but a real danger to this man's eternal life!
This is serious business, Bobby. These guys are a cult, the likes of which most of us have never believed possible. I only escaped by the skin of my teeth, and that was after years of hard work!
Unless you have been a JW, its very difficult to know how to proceed and that is why there are so few success stories of actually bringing any of them to salvation. I remember the words of a pastor I met: "You used to be a JW??? Wow, I can't believe it! I've been witnessing to them for 15 years and I've NEVER heard of one being converted!"
JW's spend many hours EVERY week just learning how to counter your arguments and innoculating themselves against outside influences. They are NOT coming by with open minds!