Does he fr get demoted to A class????

No, he actually becomes SS class if I remember the spoiler correctly (๑•ㅂ•)و✧

He does momentarily but he regains his s class status and even becomes SS class. The A class demotion is supposed to be a part of the turning point in their relationship too, but I won't be surprised if they skipped it like the skipped Hyeosop's entire Argentina arc