script retuns attempt to index nil with Parent?

i am making a feature where if the car touches the water it respawns in a boat

note this script is in the car touch block and it is line 14

local touch_block = script.Parent

local car = script.Parent.Parent
local car_transparency = car.transparency

local respawn_boat_found = touch_block.trigger_respawn
local touch = touch_block.Touched

local boat_name = touch_block.what_boat_is_found

local function respawn(boat)
	touch_block.Orientation = Vector3.new(0, 0, 0)
	
	boat_name.Value = boat.Parent.Name
	if boat_name.Value == "respawn_point" then
		boat_name.Value = game.Workspace.respawn_points.respawn_point_1
		script.Parent.Parent.properties.can_be_damaged.Value = false
		car_transparency.Value = 1
		touch_block.Size = Vector3.new(1, 1, 1)
		--repeat
			repeat
				wait(0.1)
				car_transparency.Value = car_transparency.Value + 1
			until car_transparency.Value == 1
			repeat
				wait(0.1)
				car_transparency.Value = car_transparency.Value - 1	
			until car_transparency.Value == 0
		--until 
	end
end

local function on_touch(other_part)
	if other_part.name == "boat" then
		print("found a boat")
		respawn_boat_found = true
		respawn()
	else
		warn("did not find boat")
	end
end



touch_block.trigger_script.Changed:Connect(function()
	if touch_block.trigger_script.Value == true then
		repeat
			wait(0.1)
			touch_block.Size = Vector3.new(touch_block.Size.X + 100, touch_block.Size.Y + 100, touch_block.Size.Z + 100)
			touch_block.Touched:Connect(on_touch)
		until respawn_boat_found == true
	end
end)

On line 37, you have not put in other_part as the tuple that you pass to the respawn() function. Since there is no boat variable passed to it, the script doesn't know what to find the parent of.

Put respawn(other_part) instead of just respawn() on line 37.