Exclude child from both parent and grand parent

I found the code below that exclude a child category from it’s parent’s archive, but the child category is still present in “grand parent” archive. I have a category listed as: News, European Union, Approved legislation from Parliament. The last category is just an auto updated category that should not be listed on front page (handled through interface) nor in “News” section or “European Union” section. How would I be able to achieve this, and also for future reference: how to nest these kind of issues indefinitely?

Grand parent’s category number is 3,
Parent’s category number is 1169 and
child’s category number is 2184.

function exclude_categories() {
$excluded = array( ‘2184’ );
if (is_category(1169)){
set_query_var( ‘category__not_in’, $excluded );
}
}
add_filter( ‘pre_get_posts’, ‘exclude_categories’ );

Thanks =)

And by the way. The attached code doesn’t work properly. It leaves child posts in parent.

That is not my issue.

I’m referring to this post answered by Andrei: https://forum.tagdiv.com/topic/categories-6/

where child posts are visible in the archives. When you click in on a sub heading on site: http://eu-uutiset.fi/wp-content/uploads/2017/03/categor_parent.jpg

then it would be nice that the child posts of that sub heading isn’t visible, like it is now:
http://eu-uutiset.fi/wp-content/uploads/2017/03/categor_parent_fail.jpg

According to Andrei the following code should have worked:
function exclude_categories() {
$excluded = array( ‘2184’ );
if (is_category(1169)){
set_query_var( ‘category__not_in’, $excluded );
}
}
add_filter( ‘pre_get_posts’, ‘exclude_categories’ );

and it works partly. This is from parent:
http://eu-uutiset.fi/wp-content/uploads/2017/03/categor_parent_fail.jpg

it shows that the child posts are visible, but sowehow they have been placed further down on than without that code.