I have to agree with Phil in saying his quality of life will improve
greatly if you treat his diabetes. Also, since he has kidney disease,
are you giving him sub cutaneous fluids a few times per week? You can
do this at home inexpensively, and it really improves their quality of
life.

Also, what are you feeding him? I can't remember if you addressed this
in your earlier posts. I strongly suggest that you feed a wet, grain
free diet. This is important both for the kidneys (more moisture) and
diabetes (he doesn't need carbs from dry food). Here is an excellent
article on feline nutrition: http://www.catinfo.org/

Please keep us posted. It's hell watching our pets age.

Rene