Have you tried any probiotics? One that many j-pouchers use or have used is VSL#3DS and there are studies including the following:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1773918/
This study uses a smaller dose of VSL #3 where many of us have used the prescription strength VSL#3DS where DS means double strength. 900 billion probiotics.
There are other studies on it this was just the first I found when I searched for them on-line.
I was rotating 2 different antibiotics for a long time including about a year before my j-pouch failed. I am not a success story but there are many on here that it has helped. (My j-pouch failed, has been removed and I now have an ileostomy.)
The VSL #3DS is the only one that many insurances cover at this prescription strength. You need to take it hours away from the time the antibiotic is taken. This is because it is good bacteria and antibiotics kill all bacteria. Therefore you need to take them apart from each other. The theory is to add back in good bacteria after antibiotics have killed both the bad and good gut bacteria.
Just thought I'd tell you about this for your consideration. If you do a search on here you will find threads of us discussing it and other probiotics. It would be wonderful if your husband could be seen at a Mayo Clinic or Cleveland Clinic. There are wonderful j-pouch specialists there. There's 3 Mayo Clinics and at least 2 Cleveland Clinics in the USA. I thought the VA referred patients to other specialists when they didn't have them working for the VA. I don't know if this was just proposed or if the VA adopted the ability to refer.