1: If he mentions all the bad things Israel did, point out that God rejected them as a whole because of it.
2: As for disfellowshipping, there's some great info here:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.jwfacts.com/watchtower/disfellowship-shunning.php&ved=2ahUKEwjYoNi6o-7gAhXhmuAKHfOoBtUQFjAAegQIBhAB&usg=AOvVaw0nhYmwG8UG64W--oSTwCSs