It always will when active. Once you set the control mode and parameters it will always try to maintain them. Additionally if you have flight director enabled

It always will when active. Once you set the control mode and parameters it will always try to maintain them. Additionally if you have flight director enabled it will alter the mode and parameters at specific points in the flight for you automatically. A pilot putting enough force or enough deflection on the controls will automatically disable autopilot and sound the general caution. So it's very lucky he stayed within the autopilot activation envelope.