House wrap, (Tyvex) is intended to repel water while allowing water vapor in the walls to escape into the outdoors. It HELPS wind penetration, although it isn't really intended for that. If you have wind penetration at your windows, chances are the contractor didn't install or seal around the windows correctly. A good fix for that is expanding foam, which you should explore while the siding is off the house.
Don't sign off on this 12" concept, get a second professional opinion. In addition, find out who made the siding and get their installation requirements, which are also tied to THEIR warranty. I'll bet there's a lot to learn there that will help your case.
If your contractor becomes uncooperative, you have many means at your disposal to get your house back in shape. He will have a bond, his reputation, and "industry standards" to answer for. Consider an attorney for consultation on these issues, but give your contractor an opportunity to do the right thing first.