How do you get value of texture progress in another node and delete the node at a certain value?

Question

Control
|TextureProgress2
||Sprite

So here is my attempt at the code(it is in c#). Sorry I have no idea what I am doing.
I am trying to get the value of TextureProgress, and there is an error saying that it
does not exist in current context. Also, remove_child also does not exist in current context. When can these functions be used?

public class TextureProgress2 : TextureProgress
{
public override void Ready()
{
var val = GetNode("TextureProgress2");
if(val<100)
{
removechild("Sprite");
}
}
}