How has Mr. Childs changed since Stick left the house?

I'm not sure what chapter you are referring to, but after asking Stick to leave the house, Mr. Childs becomes more protective of Sam and forbids him to have anything to do with the Black Panthers. He isn't only worried about their opposing viewpoints, he's afraid for his son's safety.

Mr. Childs also increases his presence in the "nonviolent" movement, planning a demonstration, and carefully making sure that everything is in place. After he is stabbed at the demonstration, Childs becomes even more protective of his sons. His belief in nonviolence continues, but his dedication to his family and keeping them safe moves to the forefront.