>>715628404It's moreso you have to ease them into it. A crazy person rarely realizes they're crazy. THEY think they're fine or at the least whatever is wrong isn't because of them. Imagine someone walking up to you and telling you that you're a wholly different person. That everything you know about yourself is wrong. That'd come off as nonsense because you know who you are. They're trying to convince you that your perception of reality is wrong and that them trying to break your perception of reality is actually them helping you.
In the case of Cloud, he was having mental episodes at random points throughout Midgar. The mere sight of the Reactor brought him back to the Nibelheim Reactor. And Cloud's recollection of Nibelheim somehow had both highly accurate yet completely wrong information at the same time. There was no way Tifa was ever going to just rip that band aid off