You know, and this is a pure SWAG (Scientific Wild-A$$ Guess), he may have had that BIG pee because he's holding it a bit, afraid that there will be pain. Once he learns that won't happen, you may see more normal urination. Cats avoid what hurts, which is what leads them to avoid the litter box when a UTI or digestive issue starts, in the first place.
BUT...he IS eating, and that's wonderful! I have a sneaking suspicion that he'll continue to improve daily, if not by leaps and bounds, then by baby steps.
BUT...he IS eating, and that's wonderful! I have a sneaking suspicion that he'll continue to improve daily, if not by leaps and bounds, then by baby steps.