Access GameObjects Parents and Childs from any level of hierarchy

Hi there, I am having a hard time trying to access an object from a script. The hierarchy levels looks something like this

 parent
     child_0
         child_2
     child_1

I have a Script attached to child_1, with a collision controller. How can I access to child_2 from the script in child_1 to enable child_2, which is disabled by default? I have tried a few ways, but I can't figure it out. I can, for example, do something like (I didn't try it, I don't know if this works):

 GameObject.Find("parent").gameobject.GetComponent<Transform>().GetChild(0).gameobject.getComponent<Transform>().GetChild(0).gameobject.setEnable(true)

But I suppose there should a way to access it from child_1.