The kid continues to respond well to treatment. They're going to take him off the IV antibiotic drip and try for oral antibiotics, especially since he's now keeping everything down without an anti-nausea drug aid.
The current working theory is that it's possible for otherwise benign GI tract bacteria to make their way into liver bile ducts where they metamorphose into malignant monsters o' doom. This is rare, but might be the cause of Seamus' problems.
If he has continued to improve for tomorrow morning, he'll probably come back home around lunch time.
And, boy howdy, am I going to check into pet health insurance. I'm spending more on his medical bills for this one episode than I have so far all year for myself including hearing aid batteries and apnea related joy. (Well, out of pocket cost. I have insurance, of course.)
I can't help but wonder what much poorer folk do when one of their pets are in similar predicaments. $800+ just before Christmas doesn't bode well for a very Happy Holidays for most anyone, especially the less well off with sproglings.