no-poo help?

Hy husband and I both started no-pooing about 2 weeks ago, and I am quite impressed with it. My hair has had virtually no adjusting period, and looks and feels great! My husband on the other hand, is not so lucky. He has always suffered from dandruff/psoriasis and I am really hoping this would finally clear it up for him. So far, no such luck. His scalp is dry and flaky looking, but it does seem to have changed. There are big dry patches, but not so many flakes are actually 'falling' I usually put about 2 tbsp bs and 1-2 tbsp of honey in a water bottle and mix it with about 3cups of water. That is enough for both of us. Then I but about 2 tbsp acv with about 3 cups of water to rinse. Am I doing something wrong? any suggestions?? thanks, Mel