How do I change the property of a local player's health?

texture = "Texture of the Tshirt"
local Door = script.Parent
function onTouched(hit) 
    print("Door Hit") 
    local human = hit.Parent:findFirstChild("Humanoid") 
    if (human ~= nil ) then 
        if human.Parent.Torso.roblox.Texture == texture then
            Door.Transparency = 0.7 
            Door.CanCollide = false 
            wait(However Many Secs you want to stay open) 
            Door.CanCollide = true 
            Door.Transparency = 0 
        else 
                        human.Health = 0
        end 
    end 
end 

script.Parent.Touched:connect(onTouched)

There, put this under the door.

Why don't just do this?:

local shirt = "id of your shirt"
local player = game.Players.LocalPlayer
local door = script.Parent
function onTouch(part)
    if player.Character.Humanoid.Torso.Texture == shirt then
        door.Transparency = 0.7
        door.CanCollide = false
        wait(2) -- Wait 2 seconds before blocking again the door
        door.Transparency = 0
        door.CanCollide = true
    else
        player.Character.Humanoid.Health = 0
    end
end

door.Touched:connect(onTouch)

You wouldn't want a LocalScript for this and neither of those use GamePasses. I would do something like this-

local GamePassId = 0 -- Put your GamePassId here
local Lethal = true -- Set to false if you don't want it to kill
local OpenTime = 3 -- Time the door stays open in seconds
local GPS = Game:GetService("GamePassService")
local Players = Game:GetService("Players")
local Door = script.Parent

Door.Touched:connect(function(part)
    local plr = Players:GetPlayerFromCharacter(part.Parent)
    if plr then
        if GPS:PlayerHasPass(plr,  GamePassId) then
            Door.CanCollide = false
            Door.Transparency = .5
            wait(OpenTime)
            Door.Transparency = 0
            Door.CanCollide = true
        else
            if Lethal then
                plr.Character:BreakJoints()
            end
        end
    end
end)