Definitely a mix, and if he will accept it, more wet than dry with his age, it is better for his kidneys. I would ring and ask them today what he is currently eating, or buy a small bag of what they have recommended just so you have some in for him straight away. I Wouldn't feed SCience Plan, I dont think the ingredients are good enough for the cost, similar to Iams really - PAH have their food on offer this weekend.