Get bool value from child game object

I have two game objects- Player and Box(prefab). Box also has one child object (BoxArea) which basically has just an invisible box collider component set as a trigger. OnTriggerEnter2D function inside BoxAreaScript (child game object) detects if there was a collision between Player and area around the Box (invisible collider). The boolean inside that functions then changes to true (isInArea = true). There is also OnTriggerExit2D function that sets isInArea to false once player is no more in the area. Now I want to access this bool variable in PlayerScript but firstly I don’t know how to connect those two files and secondly how do I get the actual value of variable and not the one set in the beggining of the BoxAreaScript: isInArea = false;
Thanks in advance