1. A vehicle control apparatus for a vehicle that is a hybrid vehicle having an engine and an electric motor as a travel driving source, the vehicle control apparatus comprising: an engine control unit configured to control an operation of the engine; a motor control unit configured to control an operation of the motor; a hybrid vehicle control unit configured to: specify target torques of the engine and the electric motor to achieve a target vehicle behavior of the hybrid vehicle by causing the engine and the electric motor to operate in cooperation, and cause the engine control unit and the motor control unit to operate the engine and the electric motor based on the target torques specified, and a vehicle behavior estimation section configured to detect an actual vehicle behavior of the hybrid vehicle and determine whether a first separation is exhibited in the hybrid vehicle between the target vehicle behavior and the actual vehicle behavior; and a control target instrument estimation section configured to: estimate an estimated behavior of each of the engine and the electric motor being operated in cooperation based on the target torques specified, detect an actual behavior of each of the engine and the electric motor, and determine whether a second separation is exhibited between the estimated behavior and the actual behavior in each of the engine and the electric motor, wherein when (i) the first separation is determined to be exhibited in the hybrid vehicle between the target vehicle behavior and the actual vehicle behavior, and, simultaneously, (ii) the second separation is determined to be exhibited in one of the engine or the electric motor between the estimated behavior and the actual behavior, the hybrid vehicle control unit is further configured to: calculate anew a division of necessary torque between the engine and the electric motor to permit the one of the engine or the electric motor exhibiting the second separation to be assisted by the other one of the engine or the electric motor, and instruct the engine control unit and the motor control unit to operate the engine and the electric motor, respectively, based on the division of necessary torque that is calculated anew.