Dementia didn't stop then president Regan, hasn't even stopped modern republicans from loving him. The failure of "Reaganomics"/War on Drug/Long-term-International-problems doesn't ever factor in. He's still the best. Don't see how it would change anything here.
It's not hyperbole to say conservatives don't care if their politicians have a functional healthy brain, it's literally just a fact. Mitch McConell is another great example of this.