There’s plenty factual stuff to use that far right people hate though:

• Being in the military with zero people skills means he was an ineffectual leader and a desk driving paper pusher

• He wears eyeliner

• He grew a beard to hide his weak chin

• He’s a white nationalist with a minority wife who looks like she’s at gunpoint every time she’s on camera

Again, inventing a lie to attack him with will just galvanize his supporters. Use what’s already true and very conflicting with far right ideology.