Just explain that antifa calls anyone opposed to international communist revolution a ‘fascist’. Unless your parents are communists, they are ‘fascist’, and antifa would have them exterminated. Ask them if they believe in capitalism. Capitalism is ‘fascist’ to antifa. Send them to international or local antifa sites on the internet and see if they agree with what is said on those sites. I assume that they are not avowed violent communist revolutionaries, so they must know that they are targets of antifa.

Kick em out of the house and disown them.

Everyone is anti-fascist and everyone thinks Blacks Lives Matters.... is that all there is to it? that was easy