Even in the natural realm we know that a healthy physical body does not make decisions or take any action apart from the head. It is the head (i.e., the mind) that determines what the body will do. Indeed, the body cannot properly function apart from the head. When the body is disabled due to injury or disease it means either the body is unable to carry out the instructions of the head or the head is unable to give instructions to the body. We rightly observe this as something that needs medical attention.
Were the head to be separated from the body the result is immediate death. Equally obvious is the fact that the head can take no action without involving the body.
We must not force this metaphor to an extreme and suggest that Jesus is unable to do anything without us; but we can certainly say that Jesus, as the Head of the Ekklesia, will not do anything without involving His Body.