I don't know that the tips I have would be of any help to your hub. If he's tried medications, patch, gum and all those other things, then my little remedy might not make a dent.
Anyway, FWIW, here it is...
When I was preparing to quit smoking many years ago, I did the following:
1) Picked a date. My New Year's Resolution that year was to quit smoking by my birthday. Since my birthday is in October, I had lots of time to plan, and commit myself to actually doing it.
2) I told no one. Not family, not friends. No one. I didn't need the added pressure of living up to other people's expectations as well as my own. (I had a friend who told everyone. She needed the pressure of her social group to prevent her from slipping. Your mileage may vary on this one).
3) I gradually cut down the amount I smoked each day. Started with the easiest ones first, the ones where I would usually let the cig burn down in the ashtray, rather than actually smoking it. Then gradually the harder ones, until I was down from about 1 pack per day to 5 or 6 cigs per day.
4) I took up lots of aerobic exercises. I started walking and riding my bike everywhere.
5) A month before quit day, I got rid of all ash trays etc. from my apartment, and got a big glass jar. All cigarette ends went into the jar. The jar looked horrible. Filthy and smelly, and nasty with all of those cig ends, bits of ash and general nastiness.
6) Just before quit day I took a week vacation from work. I did most of my smoking at work, and it was important for me to be away from all my usual haunts while I was re-tuning my body.
7) Filled up the "butt jar" about 1/3 full with water, over all of the cig ends. Whenever I felt a strong craving, I would open the jar and inhale deeply. The stench made me sick enough to put me off for a few hours. Managed to get down to 1 or 2 per day this way.
8) On quit day, I just stopped. Whenever I felt a craving, I would open and inhale the stench from the butt jar, and then go off and do something else to keep myself occupied.
9) Came up with a plan for what to do when co-workers wanted me to join them for a smoke break. Such as, going for tea break at a different time and in a different place than usual, going for a walk around the block while everyone else was smoking, and joining them afterward, etc.
I had tried to quit several times before I did the above, but for some reason that effort stuck. It's been 15 1/2 years since I quit, and I was a heavy smoker who LOVED smoking.
I wish your husband luck in his goal. It's a really hard thing to shake, but it's incredible what a difference it makes when you do.
Trinity