Good luck, and have patience with him. If it gets bad just walk away and let him have a moment. When I quit a couple years ago I lost my mind when I was trying to cook rice and it burned. I flipped out over 79 cents worth of rice, and my wife caught the wrath just because she was there. Not my proudest moment. It's a miserable way to feel, but the worst part of it only lasts a couple of weeks, and it will get better. Good for him for quitting instead of turning to tobacco instead, nasty stuff all of it. Nicotine gum or lozenges help a lot, makes it easier.