There are a few things that helped me, but I have heard that for this, time usually heals it. Time did not help for me, only surgery and injections. Please extend my sympathy to your husband. This type of pain is no joke. Mine ended with surgery and it is much better now. It seems like your hubby's was caused by the surgery. How awful. I suffered for about 13 months prior to surgery.
Here's a few suggestions: If you have access to a warm swimming pool, it helped me to put my arms on a floatie and let my legs dangle in the water in the deep end. 2 different therapists told me to soak in an Epsom salt bath. I had a soft pool toy that I would lay on in the bathtub because the tub was too hard to lay on. If I got in there just right, it would give me a bit of relief. The hard part was just getting in the tub in the right position. I burned out 3 cheap heating pads before the therapist suggested the Thermotex infrared heating pad. I don't know if it's worth the money I spent, but it's very durable and there was days that I had it on my leg constantly. This one also does not get so hot that you accidentally burn yourself. I would put it on a pillow and lay my leg on the heating pad. Don't use a heating pad near his incision. it helped me to put heat lower on my leg. Also, walking with a cane helped get the weight off that one side. Make sure you get a therapist or a YouTube video to show you how to properly use a cane. The therapist I had at the time had me doing very slow movements kind of like tai chi. She told me that the piriformis muscle can sometimes swell and impinge the nerve so we did very gentle movements to try and loosen that muscle. She said it's a very deep muscle on the side of your butt that takes a long time to heal. She said sometimes it's the muscle that is impinging the nerve and sometimes it's the nerve itself that is irritated. You can't really tell for sure. One other exercise is to stand on a small stool or stair step with the good leg and dangle the bad leg. That gave me a minute or two of relief at times. Did he try a recliner instead of a bed? I had to sleep in a recliner for months. Even the strongest pain medicines did not help, but did take the edge off enough for me to sleep. Don't underestimate the power of Aleve. It will kill your stomach but make sure you are adding an anti-inflammatory every day to whatever pain meds he is getting. I've had kidney stones, a baby, gallbladder pain so some pretty painful things, but the sciatica tops them all. I had steroid injections that also helped, but they didn't help for very long. However, when I did get some relief from the injection, it was awesome. If your hubby has back trouble, I'm sure he's gone down the steroid injection road already. If there's a position he can get in where he is comfortable, just stay in that position for as long as possible. When it's a nerve issue and not a muscle issue, the nerve has to heal so keeping it still and out of pain is the way to go. It's counterintuitive because prior to having the sciatica, exercising always helped my back feel better. Not so with the sciatica. The only relief I got was pillows under the bad leg on the recliner and laying a bit more on the good side in a semi fetal position and then I would stay in that position for as long as I could. One more suggestion is get a raised toilet seat or a padded one. sitting on the toilet was the most painful position I had to be in. Your goal is to use positioning to stay out of pain as much as possible. Pushing yourself and making yourself push through the pain like you might do with a muscle problem will only irritate the nerve more. If he absolutely has to sit in a chair, I've found this new cushion called purple. it's at onpurple.com. I really like the travel cushion for when I have to go out to restaurants and all they have is a damned wooden chair. the travel cushion has a strap so you can carry it like a purse with to dr. appointments. Why back drs have the worst chairs in the waiting room, I'll never know. If there's anywhere people need a padded chair, it's there. I wish you much luck and healing. Let me know if anything works.