We have dealt with mites before, and I agree- it is no fun. It sounds like you're pretty on top of this, though, joojy.
(Just a side note, you said "Apparently he has mites." Is he showing signs of having mites?
This is just what we did:
COMPLETELY cleaned out the coop, sprayed everything with neem oil, replaced all the pine shavings, and put in lime and diatomaceous earth.
(We also scattered lime around the chicken run.)
We also got our chickens a sandbox with sand to dust bathe in, dusted them with diatomaceous, and at night put drops of oregano oil underneath their wings.
You can also dip their legs once a day in olive oil.
From what I've read, garlic really only works as a preventive, but once the bird has mites, it won't help too much in getting rid of them.
Here's a thread- you might have already seen on BYC, about mites. http://www.backyardchickens.com/t/749736/mites-mites-mites/210
Hope this helps!
Edited by SuperChickRuth - 6/21/16 at 2:04pm