How to call private function from Controller to another Controller (Plugin)

Need Help
1

I have a plugin Events,

I would like to add this part

UsersController.php

   private function sendResetEmail($url, $user) {
    $email = new Email();
    $email->template('resetpw');
    $email->emailFormat('both');
    $email->from('no-reply@naidim.org');
    $email->to($user->email, $user->full_name);
    $email->subject('Reset your password');
    $email->viewVars(['url' => $url, 'username' => $user->username]);
    if ($email->send()) {
        $this->Flash->success(__('Check your email for your reset password link'));
    } else {
        $this->Flash->error(__('Error sending email: ') . $email->smtpError);
    }
}

To this part

EventController (INSIDE PLUGINS)

 $event = $this->Events->newEntity();
    if ($this->request->is('post')) {
        $event = $this->Events->patchEntity($event, $this->request->data);
        if ($this->Events->save($event)) {
            //function send_mail to user who crated Event
            EventManager::instance()->on(
            'Model.Events.afterNotify',
            $aCallback
            );
            $this->Flash->success(__('The event has been saved.'));
            return $this->redirect(['action' => 'index']);
        } else {
            $this->Flash->error(__('The event could not be saved. Please, try again.'));
        }
    }
2

Try to setup a listener https://book.cakephp.org/3.0/en/core-libraries/events.html#registering-listeners

You could also see if anyone has done any videos on youtube on cakephp 3.x events.