Muichiro survived the infinite mansion fight.. they killed Muzan and with Gyomei, Sanemi and Genya’s help he killed Kukoshibo . The survivors are all traumatised badly because of it, he have nightmares almost every night, he flinch whenever someone touches him suddenly. Even Tanjiro try to help him but he always stay quiet and doesn’t talk Muichiro was now laying in his bed, it was soon 8PM but he didn’t had moved since the morning, you come to his room for take care of him too