Although I'm glad you're here and I am so sorry for your situation, your family needs more help than will be available to you on a computer site. You, your wife, and your stepson deserve a second, third opinion and some real intervention/help. That this has gone on so long means it won't be a quick fix; there are many aspects to what is going on.

What does your stepson say when you talk about this with him? Does he realize it is a problem and that it is not acceptable? Have you ever suggested that he not be allowed in the car, at the dinner table, out of his bedroom...unless he is clean? What does he do with his time? Do his friends mind that he is this way? Does he go to school this way and if so, what does the school say about it?

If your wife and stepson won't go to therapy, I hope you will go for yourself as you have quite a bit to deal with here.

Best wishes to you and your family.