What did Captain Keller mean by, "the house is at sixes and sevens from morning till night over the child"?
The phrase “at sixes and sevens” means that everything is thrown into confusion because of Helen’s uncontrolled behavior. The phrase comes from a dice game, when everything is bet with a very high risk by rolling either a six or seven.
Helen has been allowed to have the run of the house, as her family believes she cannot be trained because of her disabilities. She takes what food she wants from the plates of others at the dinner table, and is not taught to sit down and eat like the rest of the family. If she is thwarted in anything, she throws a temper tantrum. The entire family must adjust everything they do to make way for Helen. It is for this reason that Captain Keller sends for a teacher from the North, though he is skeptical about how much Helen can be taught. The family cannot long continue in the midst of such chaos. The only other option is to send Helen to an institution for the mentally ill.