It’s always sad to see a country-based instance go, they bring together a nice community, and it’s an opportunity to learn more about the country.
Maintaining an instance is a lot of work, so this decision definitely makes sense if the admin didn’t have the time to take care of it. Hopefully the other instances are still going strong.
The content will not be lost, because each federated instance keeps its own copy.
I believe images are only hosted on the original instance.
For example if you browse this post on lemmy.world:
https://lemmy.world/post/13015119
Respective images are shown directly from the original instances, for example: https://sh.itjust.works/pictrs/image/c7285a60-c7ee-4013-8d96-6c13a541c2f0.jpeg
For text posts, I understand that they are copied across instances. But will they remain visible when an instance is completely removed?