Focus on your 12 and 15 year old. Make sure you are building in them the tools to counteract the behind your back indoctrination that your older son has been drawn in with. Make non-witness life fun for them. Teach them realities of life because the JW is empasizing everything that is bad or going wrong and using JW teaching as the only thing good and the only solution.
You need some help to switch yourself to positive thoughts and actions, you have been on the down side for a few years now about all of this. It's no doubt taking a toll on you and if your kids see this, only feeds into the JW indoctrination that dad needs "The Truth".
Have you tried approaching your wife with interest in her religion? Have her explain things to you. See if you can get her to research things that you don't understand. You of course have to be able to do this in a way that is genuine and doesn't attack. Have you read Hassan's books yet? If not, and you are serious about not being the victim of Watchtower abuses, you need to get it and educate yourself on how to counteract the cult influence. It isn't an overnight process, it is in most cases a long process requiring patience.
You don't really need the first book by Hassan, in my opinion, although very helpful, it would probably do your wife more good because it shows the similarities between Hassan's experience and how JW's work without ever mentioning JW's.
His second book, recently updated, is more about helping those who are in cult-like groups.
http://www.amazon.com/Freedom-Mind-Helping-Controlling-Beliefs/dp/0967068819/ref=sr_1_1?ie=UTF8&qid=1359931558&sr=8-1&keywords=freedom+of+mind
Take control. Learn how to get on the offense in this situation. Your family is worth saving I'm sure.