Cradle cap is normal. My baby girl had it. I put olive oil on her head and it made a huge difference. Yes eczema is almost always related to food allergies . Sometimes it can be caused by an essential fatty acid deficiency. Just keep an eye on it. Do your research on eczema but don't listen to the doctor. They usually don't know a whole lot. YOUr husband may have food allergies as well. Dairy, soy, and gluten perhaps.
I have always read that the the skin is a reflection of liver health. YOur husband should consider changing to a mucusless diet and cleanse. Oj fast check the Ask Barefoot Herbalist Forum