If you look at the top answer of the question you found you can read that the user found the hook wpmu_deactivate_blog
on wpseek.com.
Searching for delete_blog
got me here: delete_blog. I think delete_blog
is the hook you’re looking for. Try it and maybe you can confirm it yourself.
From the WP3.0 source:
delete_blog
is an Action hook that’s fired in the wpmu_delete_blog
function.
function wpmu_delete_blog( $blog_id, $drop = false ) {
global $wpdb;
$switch = false;
if ( get_current_blog_id() != $blog_id ) {
$switch = true;
switch_to_blog( $blog_id );
}
$blog = get_blog_details( $blog_id );
/**
* Fires before a blog is deleted.
*
* @since MU
*
* @param int $blog_id The blog ID.
* @param bool $drop True if blog's table should be dropped. Default is false.
*/
do_action( 'delete_blog', $blog_id, $drop );
By the looks of it, the function switches to the right blog before firing the delete_blog
action hook.