Nic, when Jarv had HGE he was like that at the vets - took him 2 days to start responding to anything so KEEP POSITIVE. They sent him home after he was re-hydrated and pumped full of anti-b's because they couldn't get him to eat anything and thought he would do better in his home environment. When we got him home he went outside and laid on the grass and didn't move for 4 hours - listless wasn't the word. It took me a day to get him to eat a bit of chicken but we got there.
They're pumping Rodaidh full of stuff to re-hydrate him and to kill any kind of infection - no wonder he's listless and lethargic. They've ruled out a blockage I'm assuming (from the x-rays) so I assume they're waiting for bloods back?
It's the worst thing in the world being far away when something like this happens - he's in good hands Nic, and we're all willing him to get better as well.
Keep us posted