I highly recommend reading more at catinfo.org. They have a lot of really great info on diet transitions and how to do it safely (slow is key!).
If you want to do a high quality diet for your boy, you don't necessarily have to go full homemade. If you can find somewhere near you that sells Nature's Variety Instinct frozen raw food, you can use that. It's what I feed my cats (you may find it only as "dog food", but it's complete for cats, too). And yes, they drink less if they're on a raw/homemade diet, simply because they're getting their moisture the way their bodies are designed to, from their "prey".
Alternatively, there are places you can purchase different meats online. You'd need a freezer to make it cost effective, since you wouldn't want to be ordering small batches, but it's something to consider, anyway.
A healthier diet in general will help with your boys fur, as well. Good for you for trying to make the changes necessary to help him be healthier! I hope he's cooperative. Some cats can be very picky about their foods and make transitioning difficult. While you researching, you might also look into getting some canned foods for him. Contrary to popular belief, they aren't bad for his teeth, and it might help with later transitions to get that added to his diet now.
