What mg levels of his meds has he reached?
 
How many times a day is he getting Pred?  The optimal action window for
that med is about 9 hours so giving it every 8 hours helps some.
 
Is he getting Prednisone or Prednislone?  (Pediapred is Prednisolone.)
The liver converts Prednisone to Prednisolone bu tin some ferrets that
liver function is impaired so having Prednisolone can work better.
 
Some ferrets are more helped by the injectable rather than oral.
 
Remember that in end stage insulinoma it isn't unusual go above the
usual recommended max if the ferret has to counter-indication.  After
all, if you are between death and trying something...
 
Sweet liquids around all the time will reduce his nausea at this stage
and will help with his blood glucose.  You can use a range of things
from the syrup from canned peaches in sugar syrup to Nutrical smooshed
into water with forks and the milky looking oil film removed.
 
The vet of one FHL member will at time do surgeries on ferrets who seem
to have just begun end-stage and now or then it gives a good chunk of
extra time.
 
[How about trying Proglycem now?  BIG]
[Posted in FML issue 4686]