Buttercup has had dry and flaky skin about 2 weeks after I got him. I know the reason that he has the dry and flaky skin was because of me being stupid and giving him a bath every 2 days, but that was before I knew any better. Please don't judge me on that

Well I have been using Petsilk moisturizing shampoo from day one. I only bathe him once a week now with the same shampoo but his skin is still dry and flaky. Every time I brush his hair, the flakes start to come off. Could it be the shampoo I'm using? If so, what type of shampoo should I be using?
One more question, I have had 2 people tell me that Buttercup is a female's name. Is it? It's okay to tell the truth. I won't get offended.