There are a few good books out there on raw or DIY diets for dogs and cats. I tried my cats & dog on raw foods for awhile.
If you decide to do this, be sure you consult a pet nutrition book. Cats have their own special nutritional needs. It's been awhile since I did the cat diet, but I believe they need
Taurine added if you plan on giving them people-grade cuts of meat. I was able to locate it at my local natural foods co-op store. I'm vegetarian so it was really grossing me out having to handle & mix up the raw meat cuts, and with no health change in my cats, I abandoned the idea.
I can't be of any help with the diabetes, since I've never had a cat with it. Sorry.