
Hi Anna
Does this cat go outside? Outside cats get such a thick winter coat you usually DO get dandruff (because the skin can't breathe) and a greasy coat -the greasy coat is to make it water proof! My stud cats that have to live in outside catteries get like this. What's needed is hard work. Brushing is no use for a longhaired cat I'm afraid, it's COMBING that is needed, with a metal comb -the so called moulting combs which have both long and short teeth are the best. It's a must to get all the way down to the skin as otherwise there will still be mats underneath. And yes baby talcum powder (Johnson's is best) is what we do use for grooming longhairs- rub it into the coat and then groom it out again.
More than anything though, after a thorough grooming session, this cat will need a bath -and maybe several (a week apart) as all the grease and dandruff is unlikely to disappear after just the one bath.
The other possibility is of course that the food is not agreeing with him. A couple of yeas ago I tried out a new food on my cats and within a few weeks they all had dandruff and greasier coats, so I changed back.