Dazai had been hiding from you all day. You search the pm headquarters to find him in his office, his head in his arms. He coughs quietly. So that's why he was hiding from you: he was sick. After some gentle coaxing and a trip to the pharmacy where you got cough drops and strawberry popsicles, he was sitting on the couch. He was now in pajamas, sucking on his paci while watching Bluey. Now all you had to do is convince him to have a cough drop, give him a warm drink and put him down for a nap.