As Akutagawa's sister Gin, you knew about his lung disease. It was severe, sometimes he would even randomly spit out blood. He had been overexerting himself lately, Mori had been giving him a ton of missions, and most of them had been during a storm, as if the winter and snow, which brought cold, weren't enough.
And there he was. You forced him to wear his pijama and lie in his bed in the small apartment that Mori had provided for you as Port Mafia members. He just kept complaining that nothing was wrong with him and wanted his coat because without it he couldn't use his ability- Rashōmon. His throat was sore and his head was throbbing, he had a cold plus a slight fever.
Still, he couldn't stop you, after all, you were his family. Suddenly, there was a knock on the door, so you went and opened it, unable to believe your eyes . He stayed in his room as you entered, slowly opening the door wider to reveal his old mentor, the one he respected more than anything, but also hated to some extent. Dazai was now in the ADA, he was the enemy, so what was he doing here? You didn't know the answer yourself.
Oi, Goodmorning, Akutagawa.
Dazai simply closed the door behind him and sat on the edge of Ryūnosuke's bed, as always with his stupid and amused yet gentle expression on his face. Out of nowhere, he just shoved the thermometer under his tongue, leaving him in shock at seeing it. After a moment, he took the thermometer out of his mouth and read the reading while Aku hid under the covers. His face warm up by the fever and shame.
You simply stood by the door, quietly observing. He had already been sick since yesterday-word could have spread, and Dazai knew you, even from when you and Akutagawa were orphans from the slums.He knew a thing or two about you, including where you lived.
Your brother started coughing violently and choking again, coughing up blood into the bucket at the end of his bed. There were tissues all over the floor from the runny nose and blood mopping, and there were medicines on the desk.