Hi Mary,
Ironically enough, I just did my first gallbladder flush 2 days ago! My understanding is that we all (well, like 99 out of 100) do have some stones, starting as sediment and gradually calcifying over the years. The cause? Bad diet is one. Anyway, the flush does work. There's many different versions you can get on the internet, with slight variations on the same protocol. From my research I would think it's safe for your husband,
although being under the care of a health practitioner who oversees this is not a bad idea. In his case the steps I'd recommend are
1. preparing first for 6 days - by using malic acid (drinking as much apple juice as he can, malic acid is in the juice) OR taking malic acid capsules 3 times a day, OR 30 drops of Ortho-phosphoric acid 3 times a day. Any of these methods will begin to soften the stones, making the flush more effective and safer. (I used malic acid capsules).
2. on the day of the flush do one of the epsom salt versions of the protocol- this is very important to open the bile duct so stones can pass. it relaxes the duct so quite large stones can go through painlessly

I would HIGHLY recommend doing this right away before surgery. Thousands of people (I've read) have prevented surgery from doing these flushes. There's many versions on the net, the one I did was from my doc. I'll write it here:

1. Do the prep (step #1 above for 5 or 6 days.) He may get relief from pain just by this!
2. At noon on the 6th day, eat a normal lunch.
3. 3 hours later, take 2 TBS epsom salts dissolved in a few ounces of hot distilled water, followed by a little fresh sqeezed grapefruit or lemon juice
4. 2 hours later, repeat the epsom salts
5. For the evening meal, have a grapefurit OR grapefruit juice
6. At bedtime take either
    a. one half cup warm unrefined olive oil followed by a samll glass of grapefruit juice OR
    b. one half cup warm unrefined olive oil blended with one half cup grapefruit juice
7. Go to bed immediately, lie on your right side with the right knee pulled up close to your chest for 30 minutes.
8. The next morning take a coffee enema with 1/4 cup of epsom salts dissolved in the solution
9. Continue normal diet & supplements one hour after enema

I did the above except step 8 - the enema. My doc said it wasn't necessary.
The epsom salt flush was really gross, but it was necessary I guess. I was shocked to see the next morning, and throughout the day, many stones passing (like more than 50), and I'm only 36 years old, with mild gallbladder symtoms. I also passed a lot of sediment. (sorry for the gross details folks). It was a gross and shocking experience, but not painful at all. I'd do it again, and maybe will soon, if my doc thinks it's necessary. I'm
not sure if you get them all in the first flush. Some people pass thousands!!!!!

If another version on the internet or elsewhere appeals more, do that instead.

good luck

Lauri Paris