Glad to hear the doggie now has her meds, hope they take care of things and she gains weight back.

Sounds to me like that first vet was incompetent. A pancreas with insufficiant enzymes would have been easily detected with a 8 hour test on a stool sample. If the dog fails the test then they are given meds, probably what you have now, like Panacare or something similar when the dog eats. Usually solves the problem although they do have to be on it the rest of their lives. Glad your son got a second opinion. Hope things work out from here on.