The other explanation is that he's confusing the backstory from the movie Scarface for real life (when he says "they're emptying their asylums" and **** like that). Whatever the explanation is, it's not a good one for Trump.
Right wingers with any credibility and consistency at all should be using those lines about Biden being senile and old on their guy Trump. It's so much more clear how worrisome Trump's aging mental state is now that Biden is out of the way.
Of course, you could also say, "Trump isn't confused, he's lying and fearmongering." which is a great defense.