Blood and poop cultures came back negative and Oliver seems to be doing fine (no fever, etc.). The antibiotics were stopped and he is eating again! For now, he is still getting fluids through IV, but each feed is 5 ml bigger (and his IV is reduced), so by some time tomorrow, assuming he can tolerate increasing amounts of milk, the IV line can go.
During the night, Oliver decided he had enough of the gastric line and he pulled it out himself! The end was taped to his face, but he just yanked it off. For now, they will not put one on him, as he seems to be feeding quite vigorously (after not eating for two days). He went through 25ml of milk in about one minute. He is starting to be like his sister, which is a good thing.
For now, things look OK and we will see where we go from here.