Why apprehend? It's an invasion; lethal force is obviously the proper response.
The TX constitution gives the governor the authority to use the national guard to repel invasion — leaving that aside, to assert that the states cannot make such a provision in their constitutions is to assert that the states lack all sovereignty and are merely strictly subservient to the federal government.
You know damn well you would go to jail.
You can’t just gun down kids at the border.