Can Mountain Dew, the famously sugary and highly caffeinated soft drink, cure purported dementia? That seems to be the hypothesis of Rep. Erick Burlison (R-MO), who appeared on Fox Business on Tuesday to speculate about the kinds of “drugs” that President Joe Biden will supposedly take to improve his debate performance against former President Donald Trump on Thursday. Host Maria Bartiromo — who helped cost her network hundreds of millions of dollars in a defamation lawsuit by airing false claims about Dominion Voting Systems that were peddled by a woman who believes she can speak with the win…