Why My npc health gui changing only when npc death ?

local Mob = script.Parent.Parent.Parent.Parent.Parent

local Enemy = Mob:WaitForChild("Enemy")

local text = script.Parent.HealthNum

while true do

    wait (0.1)

text.Text = Enemy.Health

end

My codes like that. Health text showing 100 till when npc dead.When npc death text showing 0

So why its text only updating when npc death ?

Ty for help..