test.py

#import kivy.core.window.window_sdl2
from kivy.input.motionevent import MotionEvent
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.graphics import Line, Mesh, Rectangle, Ellipse
from kivy.app import App
from kivy.clock import Clock


class Child(Label):
    def on_touch_down(self, touch):
        if self.parent.disabled:
            print("dis")
        else:
            print("ndis")


class Parent(Widget):
    def __init__(self):
        super(Parent, self).__init__()
        c0 = Child()
        c1 = Child()
        self.add_widget(c0)
        self.add_widget(c1)


class Main(Widget):
    def __init__(self):
        super(Main, self).__init__()
        p = Parent()
        self.add_widget(p)
        p.disabled = True

    def on_touch_down(self, touch):
        return super(Main, self).on_touch_down(touch)

class Test(App):
    def build(self):
        # self.trace = Trace()
        return Main()

Test().run()