I know this is an old thread. However, I thik i finally found a partial solution to the problem of moist food for older cats. I too have a cat that needs moist food. He was in a car accident 7 years ago and is blind, had a broken jaw, and has since lost all his teeth.
I have tried many things over the years as he hates raw meats. He really loves the dry kibble I have for my other cats and desperately tries to eat it. Unfortunately it is too hard for his gums. The moist kibble I do find are treats that are expensive and horribly bad for the cat to eat as a meal every day.
I have been feeding him canned food and I stiffen it up by placing it in the refrigerator to keep it firm. Unfortunately it gets very messy when he eats. The last food I was giving him was the Hills A/D because it seemed as if he could lick it up, but it is still messy.
I have tried for years to moisten a dry food for him but that always turns out bad. The dry food just falls apart and swells from the liquid, or it gets hard as a rock.
My new solution that appears to be working is to grind up some dry food in a food processor into a rough powder and sprinkle it onto the wet food to give it a more firm consistency. It soaks up just enough of the moisture in the canned food to make it a little stiff but not hard, something he can chew on and that is not as messy. He also loves the smell.
So if any of you are struggling with some of the same issues try the reverse of what you would normally think of. Don't try to moisten the dry kibble, firm up the wet cat food with the dry. It works for me.