How to redirect a child page to its parent page.? - WordPress

Question

In WordPress, I need to redirect a child page to its parent page. When the parent page has a password protection set, the function code I have below also protects its child pages but I need that when a user goes to a child page it automatically redirects to its parent page so that it enters the password in the form.

I currently have this function added in functions.php that displays the same form from the parent page on the child pages.

// This function prints the password form if the parent page is password protected. It is called whenever 'the_content' is invoked.
function ft_password_protect_children_page_contents( $org_content ){
    if ( is_page() ){
        global $post;
        $ancestors = $post->ancestors;
        foreach ( $ancestors as $ancestor ) {
            if ( post_password_required( $ancestor ) ) {
               $real_post = $post;
               $post = get_post( $ancestor );
               echo get_the_password_form();
                $post = $real_post;
                return;
            }
        }
   }
    return $org_content;
}
add_filter( 
'the_content','ft_password_protect_children_page_contents' );

Could you also help me with another functionality: When the user enters the password in the form that is on the parent page, automatically redirect to the first child page. This only when the correct password is entered.