If you don't think he's drinking enough water, then you can either add canned food or invest in a kitty water fountain, which often encourages them to drink. My old boy has cracked pads, though, and he drinks more than I do in a day (at least that's how it seems). I've heard that putting bag balm (which is available at pharmacies and pet stores in a green tin) can help soften up their paw pads again.
He does have a water fountain and he eats canned food twice a day so he must be getting enough between them. I just couldn't think of any other reason his pads would look cracked.
I think it happens sometimes as kitties age...they get callouses and such. My vet said if it bothered me or him to put the bag balm on it but otherwise not to worry.
Marshmallow's paw pads softened up a great deal once he started taking vitamins that the holistic vet gave us. I think you can get them in a regular vet's office as well. I know the bottle they come in is white and green. I'll see if I can find out what the name of them is.
Do they have a smell of anykind that isnt quite normal? If they do, they may be infected, due to something else. Jack's pads used to split and become very hot and smelly. First it would be one paw for about 4-5 days, I would get that cleared up and it would happen to another paw right afterwards. No one could tell me want was wrong with him, but it doesnt happen anymore so I cant tell you what it was.
My cat's 1 paw did the same thing. It started out looking like it was peeling and dry, then started to look like blisters so I took to the vet. Turned out she was allergic to the litter I was using. The vet did put her on an antibiotic so she would'nt get an infection. Good Luck!