I'm no expert (I am a groomer though) BUT I usually wash Lili every 7-10 days. Every 3 days could be drying out his skin too much with that type of shampoo (not familliar with your brand).
However, if he is losing hair and scalely you may want to bring him to the vet. He may have a skin allergy or issue that could be addressed by a good medicated shampoo that would address the problem specifically.
Has he had a change in food lately? Just some thoughts.
__________________  Lili, Holly and their housekeeper Jane |