The North Face Pamir WindStopper Fleece Jacket is a great jacket that will definitely help your son stay warm this winter, especially when used in conjunction with his shell from The North Face. The Windwall 2 Fleece Jacket will also work well. They are pretty much identical jackets. With the main difference being that the Pamir Windstopper uses a fabric designed and manufactured by Gore (of the legendary Gore-Tex fame) while the Windwall 2 uses The North Face's own version of the same fabric that is comparable but not as good (hence the price difference).To be honest, in very cold environments I prefer the insulating warmth of either down or a synthetic down such as Primaloft. Such as:http://www.backcountry.com/store/TNF3596/The-North-Face-Redpoint-Hybrid-Insulated-Jacket-Mens.htmlor http://www.backcountry.com/store/TNF2435/The-North-Face-Nuptse-Down-Jacket-Mens.html