Mouse.Target.Parent not detecting headshots?

Just created an example on how to do this, Here are my scripts:

Local Script (Inside a Handle Less Tool!)

local Tool = script.Parent --make sure this is a Tool object
local RS = game:GetService("ReplicatedStorage")
local DD = RS:WaitForChild("DealDamage",30)
function HandleDamage(Target,Damage)
    local DebugMessages = true --// flip this to false if you don't want anything printed to your output!

    --// if Target == nil or Target.Parent == nil then stop execuiting and print out the reason for the stoppage/error
    if(Target == nil) then if(DebugMessages) then warn("Error: Target is nil!") end return end
    if(Target.Parent == nil) then if(DebugMessages) then warn("Error Target.Parent is nil!") end return end

    --// OK!, This thing is not nil lets see it it has a humanoid!...
    local Humanoid = Target.Parent:FindFirstChild("Humanoid")

    if(Humanoid ~= nil) then
        if(Humanoid.Health > 0) then
            if(string.lower(Target.Name) == "head") then
                if(DebugMessages) then print("Dealing Damage[",Damage,"] to [",Target.Parent,"'s Head!]") end
                --script.Parent.DealDamage:FireServer(Target.Parent, Damage)
                DD:FireServer(Target.Parent, Damage*2) -- Two times Damage for headshots!
            else
                if(DebugMessages) then print("Dealing Damage[",Damage,"] to [",Target.Parent,"]") end
                DD:FireServer(Target.Parent, Damage)
            end
        else
    else
        if(DebugMessages) then warn("Error: Target Has no Humanoid! \n ignoring....") end
    end
end
--// the Correct way to call  this function
--// Ref
--[[
    HandleDamage(TargetObject/Model, Damage amount Delt)
]]
Tool.Equipped:Connect(function(Mouse)
    Mouse.Button1Down:Connect(function()
        HandleDamage(Mouse.Target, 15)
    end)
end)

Server Script:

local RS = game:GetService("ReplicatedStorage")
local DealDamageEvent = RS:WaitForChild("DealDamage",30)

local function onDealDamageEventTo(player, Target, Damage)
    if(Target == nil) then return end
    local Humanoid = Target:FindFirstChild("Humanoid")
    if(Humanoid ~= nil) then
        Humanoid:TakeDamage(Damage)
    end
end

DealDamageEvent.OnServerEvent:Connect(onDealDamageEventTo)

Setup:

1) Create a remote Event inside ReplicatedStorage and Name the event as DealDamage

2) Create a blank Tool and disable the setting "Requires Handle" then create a Local script inside the tool then paste the above local script inside replacing the print("Hello World") text.

3) create a Normal/Sever script inside ServerScriptService and name it anything you like then paste the above server script inside replacing print("Hello World") as you did the local script.

4) add a Humanoid Npc or player to your game (this will be your target)

Checklist and workings:

1)You should have a Tool with the above local script inside your Game.StarterPack

2) you should have a RemoteEvent Named "DealDamage" inside Game.ReplicatedStorage

3) You should have a Server(Normal) Script inside Game.ServerScriptService

4) A target Humanoid

If you've checked all the above, and you have it exactly as I've explained then when you hit play and click on your target Npc/Player they should lose health, and you should have an output of text displaying what the script(s) are doing!

If you have any questions/problems then let me know here and ill get back to you a.s.a.p! :)