It's to hurt his chances for re-election. As opposed to promoting what they're good at, Republicans attack their opponent. Democrats do the same, just to a lesser degree. Although, Republicans attack high controversy topics with no evidence just to generate general outrage.
Don't know about senile and definitely not a fascist but yeah, he's on the more conservative end of neoliberalisn (a center right to right wing ideology) which by definition makes him right wing.