That was a big Biden gaffe but to his credit, the staff apologized for the comments. Agree about lying to the public about severity of a pandemic. trump could have said something like "we're all just learning about this disease and its spread, and we're working hard to decide how to tackle it." But instead he spouts that BS that it'll go away on its own. I think he really believed it. He couldn't bear the thought that this was something he couldn't control with just his words.
If he truly believed it, then he was delusional. If he didn't believe it and was lying to save his investments, then he betrayed his oath.