What kind of blood work did he have done? I know there are some blood tests for allergies that are complete fluff, a few family members had them done before we found this out and they were amazed that they were supposedly allergic to things they ate constantly. As it turns out they basically just get a bunch of false positives for foods you ate recently.
Here's the CBC article on it:
https://www.cbc.ca/news/health/food-...lace-1.4886592
My daughter has had some food sensitivities and pretty bad eczema, she had a few different prescription lotions to clear it up and she was only supposed to wear 100% cotton clothing until she outgrew it and we still have to lotion her up twice a day. From my understanding eczema isn't caused by food allergies though, there may just be small flare ups triggered by a food sensitivity.
Has he been talking to an actual eczema specialist about it? These guys have a ton of info about it, things that can trigger flare ups, products that can help and even info on specialists in Canada:
https://eczemahelp.ca/