Did the vet check out his rumen function? If hes not eating then something clearly wrong. Did he eat many nuts?
Is there any dung?
If there is blockage / impaction you could try flushing him with a jar of coffee in a bucket of luke warm water - maybe a bag of stomach microbes too from the vet - all pumped into him.
Metacalm should cover a good few bases. Id be looking a second vets opinion, blood samples etc. No harm in chucking a magnet in and checking his liver function too.
Is there any dung?
If there is blockage / impaction you could try flushing him with a jar of coffee in a bucket of luke warm water - maybe a bag of stomach microbes too from the vet - all pumped into him.
Metacalm should cover a good few bases. Id be looking a second vets opinion, blood samples etc. No harm in chucking a magnet in and checking his liver function too.