Hi,
 
I'm sorry to say that from what you mentioned as symptoms it sounds like
your poor nine year old ferret has insulinoma.  It's a very common disease
in ferrets.  I lost an elderly rescue to it and the love of my life, my
corgi mix, Tess.  At nine, surgery to remove the insulinomas (tumors of
the pancreas) would probably be too stressful and probably only be a stop
gap measure.  Insulinoma causes the pancreas to make too much insulin,
which gobbles the sugars needed for balancing blood and energy levels.
When the surgery is done there are often microscopic tumors lurking, so a
surgery is never a guarantee.
 
Try to feed a high protein meat based food and stabilize w/ the glucose
and nutrical.  Try to use the least amount of glucose and other sugars
because it tends to cause a sudden rise then dip in the glucose levels.
In fact, you have probably noticed that once he comes out of seizure after
you've administered the glucose he should go to the food bowl and eat
ravenously.  I give my ferrets daily doses of essiac and STAT or DYNE
water (2 tablespoons to a cup of water) which I put out as a "take as you
need" basis.  Both products are essentially the same and my ferrets LOVE
the stuff watered down.  You can get one or the other from places like RC
Steele, Jeffers, and UPCO.
 
If you want to read more on insulinoma there are a number of good sites.
 
http://www.ferretcentral.org/faq/med/insulin.html
 
http://www.miamiferret.org/FHC/
 
These two are among the best and will serve as good sources of information.
 
Good luck w/ your nine year old. I have one myself and see old age
gradually affecting her more and more.
 
Sincerely,
Pat and the Furry Inspirations
[Posted in FML issue 3749]