Sam,
I just had another thought with regard to you mentioning that your husband "had just developed a bit of a complication", and I wanted to mention that it may have been there all along and not something new. I happened to ask the surgeon who did my TT on one of my follow up appointments(4 months post op), "Why is my naval off center (midline)?", and he told me it was from the small area of scar tissue next to my naval that had pushed it over. You see I'd had my gall bladder removed laprascopically in 1995 and the scar tissue had been there all this time but I never noticed it until it was responsible for pushing my naval off center.
The area near your husbands incision may have been there but perhaps the reason he didn't notice it was because of all the swelling one has after major abdominal surgery. It takes time for all that swelling to go away, and that may be why he's only just noticed it. So after all this, I'm saying again it's probably nothing to actually worry about, but of course as always you want to have the opinion of your doctor or a doctor.
God Bless,
Lou