Each case is obviously different but since we are making sweeping generalizations: People are not supposed to kick their kid out because of the negative influence he is making on the other kids. That would probably put the nail in his coffin (as secretagentyid stated). They do what they need to do R”L for his own sake. They are advised to make ultimatums so that he can make good choices or take responsibility for his bad choices. You are naive if you think kicking a kid out for being a negative influence will leave a positive impression on the other children.
