Written on 12/9/2014 for stephanericher on tumblr for the au ficlet meme:
44. one of them being diagnosed with a terminal illness au
warnings for character death as should be pretty obvious given the prompt
also late addition to the collection is late lmao
The thing was, Tatsuya was healthy, up until the point when he wasn't.
Logically, Shuuzou knew that wasn't the case - that simply things the both of them hadn't thought could be signs of sickness in actual fact were - but it had felt that way, because Tatsuya was Tatsuya. He was active, he didn't smoke, he ate fairly well, and…
And Shuuzou should have known already, that doing all the right things didn't make you immune to sickness.
It was Tatsuya. Tatsuya was never sick. And then he was, and it all happened so fast that Shuuzou couldn't get his head around it even as he took him to his appointments and took care of him because Tatsuya didn't have the energy to do a lot of things himself anymore.
Because they hadn't known, because they hadn't realised, it had been really late when the doctors finally made the diagnosis. Still, Tatsuya had seemed to have relatively good odds for recovery, and doctors worked miracles here; his own father had gotten a lot better, though he'd never recovered entirely. (He was gone now, but he'd survived so much longer than Shuuzou had thought he possibly would back when he was fifteen and it felt like he was going to have to take the driver's seat in a world that seemed like it was falling down around him)
When Tatsuya told him he was going to die, that the treatments had failed and that there was no good prognosis, Shuuzou refused to believe it, because Tatsuya never stopped fighting. He was a nasty bastard like that sometimes, even if he did tend to take on all the guilt later. Tatsuya never stopped fighting; there was always an element of rage and desperation to Tatsuya, even though he'd mellowed somewhat as he'd gotten older.
(It was later, when he was away from Tatsuya, that his mind finally processed that he was going to lose Tatsuya before his time, just like his father, and wasn't it supposed to rain on days like this?
He came home to Tatsuya with bloody fists where he'd punched the wall until the skin had broken open, but Tatsuya didn't say anything as Shuuzou put his old knowledge to use and applied antiseptic and bandages, only ran his long, gentle, graceful fingers over the places where he remembered seeing the cracks in his skin and pressed his lips against the backs and palms of his hands.)
He'd said he didn't want to spend the rest of his life sick and in pain, to grasp at just that tiny little bit more time and it broke Shuuzou's heart even as he agreed, because watching Tatsuya suffer had been the worst part back while he'd still believed that he would live.
Tatsuya had always liked to say that you shouldn't expect the world to be fair, and Shuuzou never had. But there was painful cruelty in the way the world was tearing Tatsuya away so slowly and painfully, and leeching everything that made him Tatsuya away from him before it killed him.
(It took his body that played basketball and it took the fire away, because his body was too exhausted just by being at war with itself to find the energy to kindle a spark; and it took away so many other things besides, and dimly, Shuuzou wonders if it's ever possible to be ready to watch someone die again and again this way, because Tatsuya did not die once, he died so many times in ways that mattered more than the moment that his body finally failed).
He wants to say they saw the last days coming, and that they did something special, but they didn't, because Tatsuya couldn't really move around all that much and did little more than sleep. What he can say is that they fell asleep together the night that he died, and that he woke up alone.