Really sounds like IBD....
I know the vet said they would not rx steroid due to the diabetes, but that is what is needed to treat IBD....Budesonide is gentler than some of the other ones out there. Skooter is on it and is maintaining his numbers very well on it (knock on wood)....I have also seen a lot of people on here using Predisonlone......
Sometimes you have to treat the other illness and supplementally treat the diabetes (ie trade off of treating IBD may mean a higher dose of insulin for diabetes).....
Skooter has lead a very healthy life while on his prednisone and now budesonide, and we are almost off insulin as well....