Cannot get updated value of a static property inside a static method

This is a simple example that what I’m trying to do:

class PageMake extends Controller {
  static $foo;

  public function generate(){

  static function setFoo($value){
	self::$foo = $value;

  static function create(){

I need to use the updated value if $foo inside create() method. I run an error_log() inside setFoo() and confirm that $foo was changed. But when I call it inside create() method, it return nothing.

I forgot to mention, create() is being used in filter.php:

add_action( 'wp_ajax_sendEmail', 'App\PageMake::create' );
add_action( 'wp_ajax_nopriv_sendEmail', 'App\PageMake::create' );

So maybe a was making a mistake. Because new $foo is not avaliable after page load, right?