RG suggested mange, so I looked up ideas on CZ. found a recipe to shampoo him every three days with ACV, 20 mule team borax, warm water, and pet shampoo.
plan to do that, and will continue with coconut oil (which has made the spots go from reddish pink back to his normal white skin color.)
other than that, not much going on-- he's still a happy dog.
p.s. re: link for brewer's yeast-- wow! cheap! will get when I put together more things I want from amazon so I can bulk up savings.