Sorry to hear this - yes we have had several Cavaliers with Pancreatitis [producing too much enzymes] and one with Exocrine Pancreatic Insufficiency - EPI [not producing enough enzyme].
Pancreatitis is sadly extremely painful, and does need veterinary attention.
I made my own version of Hills ID - the recipe came from a booklet they produced some years ago which contained home made versions of their diets. I found this very effective at clearing up diarrhoea episodes.
Measurements are USA cup measures but I've added my conversions!
Recipe 1 Highly Digestible diet for Dogs - cottage cheese and egg are very easy to digest
1/2 cup farina cooked to make 2 cups {Semolina, Cream of Wheat} 80g
– bring 400ml of water to the boil in a large saucepan, sprinkle in the semolina stirring constantly. Cook for 5 to 6 minutes.
1 1/2 cups creamed cottage cheese 375g {there are lots of recipes for cottage cheese on the Internet if you cannot obtain it locally}
1 large egg hard cooked {preferably free range}
2 tablespoons Brewers yeast – I use Engevita, produced by Marigold - from health food shops.
3 tablespoons sugar
1 tablespoon veg oil
1 teaspoon potassium chloride – available from E-bay
1 teaspoon dicalcium phosphate – available from E-bay, more readily available in the US.
1 teaspoon calcium carbonate – available from E-bay
Cook semolina {according to directions on packet including any salt}. Cool. Add remaining ingredients to semolina and mix well. Yield 2 lbs approx. I gave this amount to my 9.5kg dog over two days.
**Add a balanced supplement which fulfils the canine MDR for all vitamins and trace minerals eg SA37** {or a more natural supplement such as The Missing Link.}
More about both conditions here
http://www.cavaliercampaign.com/other-health-problems.htm#pancreatitis
and here
http://cavalierhealth.org/pancreatitis.htm
The dog should be given a low fat diet - need to be very careful with treats, I think you can get the Antos cereal based ones which worked ok for us. Things like sweet potato chews are good too.
I was taught to give fluids safely [vet nurse - or her sister!! might be able to teach your friend ] and keep the dog hydrated, they may be able to manage an acute attack at home - I have experience of giving injections so was able to manage pain relief and anti-nausea treatments too. [I'm a trained micro-chipper]
Unfortunately two of my chronic pancreatitis dogs were over 12, and sadly we lost both of them with very severe attacks [they were battling other problems too, and it was hard to get their regular medication into them]. I think younger dogs stand a much better chance.
EPI is managed differently, by adding enzymes to the food, and has a much better prognosis.
Hope this helps?