How to get a float from a parent object

A little of background may help. I have these units that are selectable, I want a quad with a texture to render when its parent unit is selected. “You should use a projector, a quad will glitch throught the ground” you may say, but the game is set in space, there’s no ground. My plan was to set a float to 1 as long as the unit is selected, and 0 otherwize in the script that detects if the unit is selected. I can´t, however, access that variable from the scrip in the quad, therefore, I can’t demonstrate the units are selected. How do I access those variables?

// In parent script (this will be an unit.)

public float FloatValue {public get; private set;}

// In child script (this will be the (child) quad)

gameObject.GetComponentInParent</*Script Name that Include "FloatValue"*/>().FloatValue

// but i recommand you use bool or boolean instead of using float where just need 1 or 0