How to hook a logout funtion for specific usr role in wordpress?

The wp_logout action fires after the user is logged out. They no longer have a role.

However, since WordPress 5.5.0, the hook takes one parameter: the ID of the user who is being logged out. So you might be able to accomplish your goal by using that ID instead of wp_get_current_user().

function redirect_after_logout( $user_id ) {

    $current_user   = get_user_by( 'id', $user_id );
    $role_name      = $current_user->roles[0];

    if($role_name == 'employee'){
        $redirect_url = site_url();
        wp_safe_redirect( $redirect_url );
        exit;
    } 

}
add_action( 'wp_logout', 'redirect_after_logout'  );

If you’re not using at least WordPress 5.5.0, this won’t work (and you should probably update, too).

References

• wp_logout
• get_user_by()