Cognitive dissonance. Whats happened is a form of regression. Something that happens when you are changing the way a person thinks too quickly. This happens in the psychiatric facility to some patients. They are crazy, experienced something they can't accept. If you can convince them and accept it as reality too much, it can cause them to snap back and regress the next day. Your friend might have jumped online and looked up Q and got all the media Qanon stories, and it was either accept that he has been lied to his entire life and everything is a prison he can't see, or accept the lie that everything is fine and safe, and Q is just a crazy cult. Good thing is, he is scared, that's why he snapped back so much, you can get to him, be gentle. Only show him data, and only ask him questions, don't tell him, show him. Only ask questions so he has to come to the conclusion himself.