The insulin he is on is called ProZinc... it says protamine zinc recombinant human insulin. He started out getting 2 units back on June 7th, today they upped it again to 3 1/2. I don't do home testing.. I'm not really sure how to do it.

If there is anyone near Cokato, MN that could show me that would be great! We haven't changed his food - he does eat dry cat food, turns his nose up at ANYTHING else: wet food, people food, all of it!
He has gained almost 4 pounds since June, but I noticed in the last few days it's easier to feel his spine - not as bad as it was in June, but not as good as it had been either. Let's see.. he's 10-13 years old... umm, he had been doing really super, hanging out with us, playing with the other cat - I even saw him run once! His back legs are weak, he walks on the legs, not just on the paw. He takes a pill each morning with his food to help out his joints.
I just don't know what to do. It is so strange for him not to finish his food (he eats most of it, but even leaving a few pieces for him is weird - he usually eats it ALL). And right now is his dinner time and he's nowhere to be found. Now that, is just plain strange.
Can anyone give us some advice?