I don't have a beta, so please excuse typos.

...
Every night, voices called her name, whispered and pleaded for her to wake up. For years she would wake up and look around, trying to find who was calling her awake. Finally, she decided that these voices weren't real, they were just her anxiety bubbling to surface in her dreams. After all, the only started after Eren had saved her.

Mikasa jolted awake. Her entire body felt numb and heavy. She tried closing her eyes to sleep again, but everything just felt wrong. What was that soft beeping, and where were those hums coming from? The bed she was on was angled, forcing her to sit up. Struggling to get up, Mikasa took note of her room. There were strange boxes, tubes and wires all connecting to her and each other. She sat next to a large window, curtains drawn. Mikasa put all her force into moving her body to the edge of the bed, and fell off. She crashed to the floor and multiple of the tubes and wires were ripped out. She hit her head and lay stunned on the floor, suddenly everything just hurt. Blood trickled down her left arm where an IV had been ripped out. The soft beeps had turned into a long ugly beeeeeep, causing Mikasa to shut her eyes. God where was that noise coming from. She hated it.

Mikasa didn't even have time to attempt to move again before she heard yelling. Footsteps echoed in her room and hands were on her shoulders. Another person ran into the room and the beep was turned off. Mikasa's eyes had trouble focusing as she looked at the smooth faced nurse in front of her.

"Christa?"
...
Christa with the help of another nurse (someone Mikasa didn't recognize, maybe the woman from Eren's troup?) helped Mikasa back in her bed. She rambled on about an accident and brain damage, but Mikasa didn't pay much attention. The second nurse told her not to move while she called Mikasa's family. The black haired girl visibly perked up at this. Eren

Christa kept her company while they waited for her family. The nurse chatted about various TV shows she had missed and the movies she would have to see. All she got in reply were confused glances, and a misplaced grunt. Christa's eyes softened, "Mikasa, do you remember anything?" there was a hesitation, then Mikasa shook her head, " Do you know what year it is?"

An odd question. Mikasa might have forgotten whatever got her in here, but she remembered almost everything else, "850."

This answer didn't please Christa, who looked down, "ah..." An awkward silence filled the room and Mikasa started fiddling with her fingers. They felt weak, as if they hadn't been used in a while. They weren't the fingers of a soldier, that's for sure. In fact, her entire body felt weak, she could barely move her arms and legs, and her neck would protest every time she shifted her head. Mikasa wanted to touch her neck, feel the scarf that wasn't there. She was certain that when Eren arrived he would have it for her. He knew how much it meant. Maternal instincts arose when she thought of the boy, he had saved her once, and she focused everything after that on protecting him.

Mikasa continued playing with her thumb when the door was opened. The nurse walked in (God what was her name, patre? No that wasn't right) , talking softly to her family. Following her was Mikasa's parents, looking considerably older.

"M-Mom... Dad.." her throat suddenly felt dry and hoarse. ran over and hugged her daughter, speaking rapidly in Japanese. Both woman were crying, it felt like years since they saw each other. Mikasa burried her head in her mother's shoulder, she couldn't believe it. Nothing could break her from this bliss, all she needed was to see Eren again, to get her scarf back.

A masculine hand rubbed her back; Mikasa turned, expecting a relieved Eren or Armin, but was met with... Jean? This Jean wasn't the one she knew though, he looked 10, maybe 15 years older. Around his neck was a chain with two wedding bands, god how much time had passed? He leaned down and embraced her tightly. Mikasa tensed and let out a small growl.

"Off. Get off." Jean backed up and looked surprised, "Why are you hugging me? Where's Eren?" Jean's faced dropped and he looked to the floor, "JEAN, Where's Eren? Bring Eren over." Mikasa's voice grew more hysterical. Mikasa looked over at her parents. Her mom had her eyes trained on the floor and her father's on the wall."

"Sweetie," Mikasa shuddered, why was he calling her that? There was a pause, and Jean still refused to look away from the floor. "Baby," he started again slowly, "Eren, h-he was so small, h-he didn't." Jean's shoulders were shaking now. He covered his face and suppressed a couple sobs, "H-he didn't survive the c-crash!"
...
Mikasa refused to believe this life. She was not a bubbly thirty-year-old artist living with her spouse (Why would she even think of marrying Jean, ugh). She did not have a young son named Eren who dreamed of becoming a cop. There was no car crash, no accident that rendered her comatose and Eren dead. No, Mikasa refused to believe this. She was a Titan killer, she and her friends trained together and joined the scouting legion. She was going to set humanity free with Eren.

She wasn't going to just accept her fate and sit in this bed forever. It had been two weeks since she first awoke. A couple days ago she was discharged and brought to her "house". Her "husband" kept trying to talk to her, show her pictures and tell her no sweetie this is real. She eventually got her scarf back, according to Jean, she knitted it for Eren last Christmas. Red was his favorite color, but he could never find a scarf he deemed "soft" enough, so Mikasa took it to herself to make one.

Mikasa tightened the scarf around her neck and looked out the window. She was supposed to be starting physical therapy next week- what ever that meant. Jean told her that it was to help to regain muscle strength, so she could walk again. Mikasa figured it was going to take a while to rebuild strength, they wouldn't be doing it this quickly otherwise. She had now attempting to escape 5 times, failing spectacularly.

Mikasa grabbed one of the pictures books on the bed. Jean had left them there for her, saying it would help jog her memory. Mikasa's arms were in much better shape than her legs. She figured that whatever accident hurt her legs more than her arms. Besides, judging from these pictures, she was pretty buff before.

Quickly growing bored with pictures of her and Jean together, she started looking at the other albums. Her heart swelled when she noticed one that had "Eren" written on the front, in neat, blue lettering. Flipping through it, she noticed some of these had defined tear marks on them. The one of a tired looking Mikasa holding a crying newborn had obviously been ripped in half at some point. Mikasa continued flipping through and watched Eren grow. His first "Christmas" (whatever that was), him taking his first steps, the three of them on the beach, Jean giving Eren a piggyback ride. There were even a couple pictures of Eren with a small blonde boy she recognized as Armin. All these pictures felt surreal to Mikasa. She couldn't believe this bright smiling girl had once been her. On the fifth Christmas, Eren had gotten his red scarf. Mikasa unconsciously started stroking it when she saw the picture. His face was bright and chubby as he held it up. The next picture he was wearing the scarf and giving the camera a big smile- his front tooth missing. Mikasa turned the page and reached the last picture in the book. She was holding Eren in her lap, the scarf he had just gotten was wrapped around both their necks. Her arms were protectively around his waist, holding him close. Eren was clinging onto a stuffed colossal Titan, giving the camera another wide grin. Mikasa's eyes were closed, frozen in the midst of laughter. Jean had just told me a joke she thought. Her eyes started to burn. Loud, pained sobs erupted from Mikasa's mouth as she cried.

"Eren, Eren, Eren Eren Eren Eren." She lay her head down in the book, convulsions wracking her body. She could never accept this world as reality. She was a soldier, Eren was alive and a Titan shifter.

She could never live in a reality in which her only child was dead.
...
Things that I wanted to mention in the story but couldn't:
Eren lost both his arm and leg in the car crash and died from shock. Mikasa and Christa were good friends before the accident. P much everyone in the Titan world had some real world equivalent; Grisha was the doctor that helped her deliver Eren, his wife Carla would babysit Eren sometimes, Sasha owned a deli with her husband Connie, Levi was Eren's kindergarten teacher that he loved. Mikasa didn't go into a coma immediately; she had to go in for surgery and never woke up afterwards. Jean was a high-ranking police officer, and his family has a legacy of being police officers- hence Eren's dreams of joining his Dad in the ranks.