Can you fix an OnTouchGui part that's broken?

You've got a few issues. They're all in your guigiver script.

1. On line 4, there is no function called :children. It would be :GetChildren. You could also do game.Players:GetPlayers.

2. You never defined what humanoid was before you made the if statement.

3. This isn't exactly a problem, but I HIGHLY advise you to not use :Remove, as that is a deprecated function. That means it could be removed later, and there will be no such thing as :Remove. Use :Destroy instead.

clone() should be capitalized Clone(). Not sure if there’s anything else but look in output and it will tell you everything you need to know.

Do you seriously rely on others to spoon-feed you? You clearly made some mistakes, missed ends, and using a deprecated latter. :connect is deprecated if you don't know, so use :Connect. Also, functions need to be local, global functions are bad practice to use since it's less efficient than local functions and has a small impact on performance. Local functions on the other head have an advantage over global variables since it's easier for scoping and organization.

local debounce = false

local 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 
end
return nil 
end 

local 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(2)
debounce = false
player.PlayerGui.OnTouchGui:remove()
wait()
debounce = false
wait(5)
end
end
end


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

I just fixed your script but didn't check for any errors except for your spellings and ends., if it doesn't work de-bug it your self.

Again, global variables. Also, note that HumanoidRootPart exists in all R6 and R15 characters, so never use Torso or UpperTorso when you can use HumanoidRootPart.

local sp = script.Parent
local Frame = sp:WaitForChild("Frame")
local Boss = Frame:WaitForChild("Boss")
local Health = Frame:WaitForChild("Health")
local Red = Frame:WaitForChild("Red")
local HealthCount = Frame:WaitForChild("HealthCount")
local BossName = Frame:WaitForChild("BossName")
local Humanoid = nil

while true do
    if Boss.Value ~= nil then
        if Boss.Value:FindFirstChild("HumanoidRootPart") then
            sp.BossGui.Adornee = Boss.Value.HumanoidRootPart
            sp.BossGui.Enabled = true
        end
        Frame.Visible = true
        BossName.Text = Boss.Value.Name
        Humanoid = Boss.Value:FindFirstChild("Humanoid")
        if Humanoid then
            Health.Size = UDim2.new(Humanoid.Health/Humanoid.MaxHealth,0,1,0)
            if Red.Size.X.Scale > Health.Size.X.Scale then
                Red:TweenSize(UDim2.new(Humanoid.Health/Humanoid.MaxHealth,0,1,0), 1, 1, (Red.Size.X.Scale-Health.Size.X.Scale)*10, true)
            else
                Red.Size = UDim2.new(Humanoid.Health/Humanoid.MaxHealth,0,1,0)
            end
            HealthCount.Text = math.floor(Humanoid.Health).." | "..Humanoid.MaxHealth
            --Health.BackgroundColor3 = Color3.new(1-(Humanoid.Health/Humanoid.MaxHealth),Humanoid.Health/Humanoid.MaxHealth,0)
        else
            sp.BossGui.Adornee = nil
            sp.BossGui.Enabled = false
            Frame.Visible = false
        end
        if Boss.Value.Parent == nil then
            Boss.Value = nil
            sp.BossGui.Adornee = nil
            sp.BossGui.Enabled = false
            Frame.Visible = false
        end
    else
        sp.BossGui.Adornee = nil
        sp.BossGui.Enabled = false
        Frame.Visible = false
    end
    wait()
end

No errors in this script except for a few which I fixed, if it doesn't work, debug it since I'm not spoon-feeding you.