have him allergy tested, change diet, no nightshade, losts of water,, pure.. not tap. no foods with dyes, low fat and no fast foods. restrict sugar. going vegetarian is best. don't use soap unless its basis or neutrigina. No pets. and tanning both helps too . it is the lights that help.
Sorry to hear about your nephew's suffering. I learned about a company with natural healing oils for lots of different conditions. They have a product for eczema that is reasonable and has lots of testimonials and a long money back trial period. If you want more information you can find it on my page. Take care.