DynamicCrosshair.cs

using UnityEngine;

public class DynamicCrosshair : MonoBehaviour
{
    public GameObject crosshair;

    MouseOver mouseOverScript;

    void Start() {
        mouseOverScript = FindObjectOfType<MouseOver>();
    }

    void OnTriggerEnter(Collider jennyCollider)
    {
        if(jennyCollider.tag == "Player" && mouseOverScript.mouseOver == true)
        {
            Debug.Log("Both true");
            crosshair.SetActive(true);
        }

        else
        {
            Debug.Log("TriggerTag Player but no mouseOver");
            crosshair.SetActive(false);
        }
    }

    void OnTriggerExit(Collider jennyCollider)
    {
        Debug.Log("TriggerExit");
        crosshair.SetActive(false);
    }
}