One of my sons had it bad when he was an infant. He had a rash all over his face and neck, almost non-stop for months. We primarily treated it with Aquaphor and tried to prevent him from scratching. He's mostly outgrown it, but I've noticed that sometimes he can get flare ups on his ankles and inside of the elbows. It seems to happen more when he gets hot. We did get some prescription medicine for a patch on his scalp once. It worked well and faster than Aquaphor, but since he was just an infant, we didn't want to treat with too many steroid based creams.
I'd ask a doctor if there was something your husband can take for the flare ups. And then I'd look at finding a mild bath soap and lotion that might help reduce the flare-ups and maybe help keep his skin from being dry.
When my son was affected, I did some searching online. Some people recommend some kind of oatmeal wrap to help. I never tried it though because my son had it on his face and it's hard to wrap that.
We found laundry detergent made a difference. We use Tide Free now and double rinse all his clothes. Oh, and fabric softeners can be an issue as well.