How to access Mouse.Target parent?

Hi guys, I need to get a parent of the part targeted by the mouse, I tried with something like this:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()

function myFunction()
	if tostring(mouse.Target) == "MyBrick" then
		local instance = mouse.Target.Parent:FindFirstChild("InstanceID")
		instance.Value = 15;
	end
end

But that wont work, why?

Not too sure why that didn't work, but gonna try to put my hand on it:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()

function myFunction()
	if mouse.Target then
		if mouse.Target.Name == "MyBrick" then
			local instance = mouse.Target.Parent:FindFirstChild("InstanceID")
			instance.Value = 15;
		end
	end
end

Also I hope you do call that function somewhere.