Treating a Dog's Skin Condition?

I have researched until I was blue in the face and still have no definitive answer. One of my two Cavaliers has had a skin problem since I rescued them nearly 12 months ago now. They, being brother and sister, are both almost 9 1/2 years old. My boy's skin is pretty much covered in wax like lesions which I scrape off the best I can. I also bathe him in a mixture of coconut oil, neem oil, some Dawn, and then the rest is water. Once he's chamois dried I then spray him with a small amount of almond oil and water. His condition is up and down!

Any budding scientists want to have a go at answering this lol. All suggestions will be welcome. All sugars and grains are eliminated from his diet and he is raw fed according to the Hot vs Cold Chinese therapy etc. Trust me both darlings are very spoilt by me in the forms of massage etc.