My advice is to find out exactly how much sodium and fat is recommended. Not sure why you hate Science Diet, but I can tell you that their prescription foods have saved a couple of my dogs' lives. You could also consider Royal Canin prescription foods...maybe speak to your vet about theirs?
I know you said that home cooking is not an option, but I can tell you that it is easier than you might think. I home cook for one of my very ill pups and she is doing fantastic. If you want to know more, feel free to PM me.
A site you might want to read is
Welcome to Pet Diets Lots of great information on that site. Best wishes... I hope things go well for your pup.