A. Too much baths can damage the skin and cause skin problems, so unless it is with a medicated shampoo prescribed by the vet, don't bath him anytime soon.
Obviously he might have another condition that is causing this oily skin. In order to try and find out what is the problem you need to rule out parasitic diseases first (skin scrape at the vet), then start him on hypoallergenic food or send a blood test for allergies to the lab.
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