I'm responding to your post as I have similar issues as your husband with anal ulcers and fissures. My Gi prescribes rectiv cream for the fissures or nifedipine cream. He also prescribes a numbing cream lidocaine to ease the discomfort. When I'm really struggling and in toe curling pain I take OxyCotin or Xanax.
With the surgeon's permission, your husband can try warm bath soaks. He can and should do this several times a day to ease the pain.
For someone who has never experienced how debilitating anal pain is, it can be very hard to understand and it is not uncommon to feel helpless as a spouse. The pain is constant and unrelenting and with the jpouch functioning, passing stool by this area 6 or more times a day is living HELL. I never had ulcers in my anal canal in 25 years with UC until jpouch surgery.
To help him stay calm, see if he can get pain meds. Now that he has the ostomy, thAt should help heal the area and slowly relieve the pain. However, the ulcers and fissures can be one chronic once hooked back up. I did not develop them until about a year or more after takedown but had chronic inflammation and pain almost from the first day of my takedown and forward and was getting treated for it.
I am almost three years out and deciding whether to move to a perm ostomy or not. I'm not saying this will happen with your husband. I am just providing you with some information that he may want to think about and discuss with his doctors. Best of luck.