"Ah. In that case, I shall go," Severus said, not bothering to refrain from rolling his eyes, as it seemed unlikely that Nott would notice. He had accomplished what he'd come for, more or less, although it wasn't all that satisfying to discover that there hadn't been any appreciable improvement. At least he didn't seem to be too much of a danger to himself, and he couldn't see Nott being bold enough to cause real trouble for others.
But if too much more time passed without any change, Severus thought he might just approach Goyle about some more invasive tactics. Purely for Nott's benefit, of course. "Good day to you," he said with an off-hand wave and, with one final glance up at the cat perched on its windowsill, turned to leave. It occurred to him for a moment as he was climbing the slope back to the castle that it was all quite unfortunate, but - that wasn't really worth dwelling on.