In some places it is illegal _not_ to freeze the fish for sushi, to avoid anisakis (I don't know how it is enforced, though).
source: https://elpais.com/sociedad/2006/12/20/actualidad/1166569202...
source: https://elpais.com/sociedad/2006/12/20/actualidad/1166569202...
I tried to convince him otherwise, but never got anywhere.
https://www.seriouseats.com/how-to-prepare-raw-fish-at-home-...