How to make gui only appear once a quest is completed?

I've made this quest system and a gui brick which shows a gui for the set amount of time. I want the gui to only appear when you touch the gui brick only when the quest has been completed. I've been suggested to change the bool value and set the script to understand it by true or false but I don't want to alter the already made script.

Quest Completion Marker(for reference of how the mission becomes assigned complete):

script.Parent.Touched:connect(function(touchedpart)
local player = game.Players:GetPlayerFromCharacter(touchedpart.Parent)

if player then
if player:FindFirstChild("Quest6") and player:FindFirstChild("Quest6").Value == "-[Get a Water Tank]" then
player.Quest6.Value = "-[Completed]"
game.Workspace.Data[player.Name].Socks.Value = game.Workspace.Data[player.Name].Socks.Value + 1

        end

    end

 end)

GUI Projector:

local debounce = false

function getPlayer(humanoid) 
local players = game.Players:children() 
for i = 1, #players do 
if players[i].Character.Humanoid == humanoid then return players[i] end 
end 
return nil 
end 

function onTouch(part) 

local human = part.Parent:findFirstChild("Humanoid") 
if (human ~= nil) and debounce == false then

debounce = true

local player = getPlayer(human) 

if (player == nil) then return end 

script.Parent:clone().Parent = player.PlayerGui
wait(17)
debounce = false
player.PlayerGui.OnTouchGui:remove()
wait()
debounce = false
wait(17)
end
end


script.Parent.Parent.Touched:connect(onTouch)