It is expensive but easy supplement treatment for EPI but what are the other issues? They may exaggerate the problem or be hard to treat themselves due to the poor gut absorption that EPI causes if medication would be taken for them.
EPI is hereditary and was at one time very common in german shepherds but many breeds can get it. Working breeds seem to be more likely in my experience. It is usually picked up reasonably young. I would say four years is old to be diagnosed. Nowadays it is less common due to reasonable breeders breeding it out of the lines.
In my early days working with dogs we would advise owners to buy fresh pancreas from the abattoir. It worked much better than the food supplement alternatives ( gosh am I really that old

) Unfortunately it cannot be bought that way now. Haven't heard of any new method as funky fish knows about, worth asking
your vet about it.
Good luck with him, not nice finding out any problem withyour dog without finding multiple things
