Leigh, Hanan Caine is our vet and I can assure that he REALLY knows his
stuff.  If he hasn't found a printed explanation why or how pancreatic
enzymes might help a ferret after something like ECE then that is EXACTLY
what he is saying: that there is no known reason why or how it might work
that he has YET encountered.  (There may be one which hasn't been found,
then again, there may be none at all and other factors may be at work.)
That said, when we were in a last ditch situation with 'Chopper at one
point he was willing to try it, simply because a friend of our's had luck
with it in a very bad situation.  (He is very aware that veterinary
medicine is a constant learning opportunity, and he's diligent on that
score -- I don't know when the poor guy gets time to catch sleep. ;-).)
For 'Choppie enzymes were not the answer.  The answer in her case was that
she had a form of heart disease which is not as readily apparent as the
more typical kind.  An ultrasound was essential.  She turned around for a
good chunk of time (till her heart got too bad) once she was treated.
Inability to hold weight can happen for a number of reasons, of course,
but that was the Organic Helicopter's reason.
[Posted in FML issue 2664]