Gazelle,
I had just logged out of the site here again and getting ready to get to sleep and there was a segment on a tv show here with our "Dr Harry" who is a vet. He was talking about a detangling spray-on agent that means you wouldn't have to totally bathe the cat. Apparently there are natural/organic ones which don't contain harsh chemicals. It won't get rid of the really thick mats that are there already, but it might be worth looking into for the future grooming of your kitty.

good luck with it.