I'm so sorry to hear about Archie and his pancreatitis. We almost lost our dear Zeus to pancreatitis and he had to stay in the hospital overnight on an iv. It was one of the most awful days of my life. However, the good news is that there are still quite a few healthy snacks that he can have. After Zeus was on a strict diet for a few months to calm his pancrease down we got the okay to give him apples, bananas, green beans, ect. I just can't give him anymore puppy treats, peanut butter, or that stuff. Also, if you ever want to research more food Solid Gold Holistique Blendz is for pancreatic dogs and my pups love it. It is very very very low in fat and we mix it with a little low-fat Natures Best RAW chicken and they gobble it up.
Anyway, lots of luck to you! Be sure to let the vets know he has pancreatitis before they administer any future medications because many will have bad side effects now. Oh, and diabetes can be an effect too so watch the sugar intake.
It will be alright.
Heather and the "kids."
PS: To the other person who was concerned with your pup, my boy vomited once and did not have a bowel movement and I took him to the vet. At that time he had a 50/50 chance of survival...so if you're ever concerned just take your baby to the doctor. I'm sooo blessed that I did.