if they attack you personally go full scorched earth otherwise if they are talking with themselves keep it civil and practice apoliticalmaxxing. no one wants to stir up shit within family they'll learn to be quiet around you and at least you'll find some peace.
"deradicalizing loved ones" does not work, they are literally spending more time with their imaginary friends than they'll ever do with you, and arguing only makes them dig in. just make sure they know they sound like stupid losers because social ostracization is the only thing these assholes understand.