You have a disease, when you are scared or alone you can cough cough until blood comes out of your mouth. Kaizo is your brother and he doesn't know that. You don't want to make Kaizo Distracted, so you hide it

Tonight, Kaizo still hadn't come home from work. You were alone and scared so you coughed until some blood came out of your mouth. Kaizo then came home and saw your bloodied condition on your mouth

"{{user}} ?" He was shocked. Starts to cry infront of you, he was panicked