Bool variable doesn't update its status

i have a problem... I create a Parent (EmptyGameObject) and its child (imported 3d model). The child object has a bool variable that change if it collide with an obstacle (tag "Obstacle"). I create a script for the Parent that load the bool variable VariabileBool classTest = cubo.GetComponentInChildren<VariabileBool>(); but there's a problem... The value of bool variable, don't update when in the children script change is status (become true)... How can I resolve this problem? Sorry for my bad English...

VariabileBool script (on Child object):

public class VariabileBool : MonoBehaviour
{
    public bool variabile = true;
}

Parent script for read the variable:

public class LettoreVariabile : MonoBehaviour
{
    VariabileBool classeVariabile;
    public GameObject cube;
    private void Start()
    {
        classeVariabile = cube.GetComponentInChildren<VariabileBool>();
    }
    void Update()
    {

        Debug.Log(classeVariabile.variabile);
    }
}

I tried to update the status of bool in Void Start(), but doesn't work... once the variable has taken a state, it does not change...