I agree. You either need to keep him on prescription food or homecook for him with a specific recipe developed by a nutritionist.
Chronic pancreatitis can lead to diabetes when the pancreas stops producing insulin and/or pancreatic insufficiency when the pancreas no longer produces the enzymes necessary for digestion.
Here is a good article about foods for dogs with pancreatitis:
Pancreatitis | B-Naturals.Com Newsletter
It's a good idea to add probiotics and digestive enzymes to ease the load on the pancreas, too.