Hey Jen, that's wonderful. Bless you for going through this with him.
I have been smoke free about 18 years. Frankly, I have forgotten exactly how long. I went cold turkey.
Just keep telling him it will get better. I did a lot of mental preparation prior to stopping. On a whim, I decided to see if I could go for a few hours without a smoke. When I accomplished that, I just kept going. (Instead of one day at a time, it was hour by hour) For me the first week was the worst. Second week got better, etc. I would do deep breathing until the urge pasted. And the urge always does. That first puff, when you light up, is always a deep inhale, so I thought the deep breathing might work. It did for me, but everyone is different. If there is something he can focus on until the urge passes, it might help. I also stayed away from things that triggered me like talking on the phone and smoking. I also carried around a lighter and open pack so that I would never panic over not having them available. Six months later, I threw the open pack away.
My side effects were extreme fatigue (falling asleep while reading a book to my son) and lack of coping skills. It seems like I had the shakes a little, but those passed quickly. I was never a gum chewer or eat hard candies. The breathing exercises are what made a difference for me.
Keep us updated on his progress.