"Goyle seems to think he had been improving, until recently." It hadn't escaped him that his own visit to Nott had come right before the man had unhinged again, but he couldn't think of why that would be the cause. He hadn't done or said anything of note. "You can decide for yourself. You visited him there, didn't you? Your opinion of his surroundings will mean more than mine." He didn't mind having Nott here, aside from one or two outrageous incidents. And Goyle was useful.
"I think that would be easier, considering that they may already be corrupted. But I don't know exactly how his condition has affected his mind, or his memories. I think it will take some investigation before we decide." He wouldn't object to doing the initial digging himself, not at all.