you could also in one step just use the snapping in the CC version.
Drag the null near its anchor point, and hold ctrl (cmd), this will make the snapping from point the anchor of the null.
Then with crtl pressed drag the null to the anchor of the other layer
This ofcourse only places the null at the position of the other layer.Â
Rick's suggestion will also translate all other transforms of the parent layer to the null, like rotation and scale.
Robert