Trump is having problems with dementia and being demented. He is loosing his cognitive abilities and evaluation skill. He often lives in unreality in a World HE chooses to live in even it it is not real. Declaring something as real or truth does not make it real or truth. He thinks it does.
By the way, the Nazi Party in times in recent past declared that if they said the Jewish extermination did not occur and said it often, eventually everyone would think it was a myth and did not occur. The Nazi Party thought they could create a new reality by saying something often enough to make it a truth. It bothers me that Trump and Musk seem to be purporting Nazi concepts and rhetoric. Musk seems to be very supportive of Nazis.