Set after Dove's death in Crises on Infinite Earths. I don't know anything about their parents, so that's not in any way cannon, it just fit with the story. Also, in comic book reality, shadow demons disintegrate their victims completely. I am ignoring that.
Disclaimer: I own nothing but the killer bunny rabbit of the plot.
"Don! DON!" Hank flew to the rubble burying his brother, his little brother, grabbing the shadow demon and punching it hard enough to shatter it. He scooped up all that was left in his arms, not feeling the child Don had saved tugging at his arm, not hearing the words of the grateful and consoling mother, before she ran away. He just sat there. Unmoving. Don. Dove. His life, his little brother, HANK WAS SUPPOSED TO PROTECT HIM! That was the point, that was why he was here, to protect his little brother who couldn't protect himself.
Why? Why. Why. He buried his face in the tatters of his brother's chest, his brave little brother, who was so willing to put anyone's life above his own. There was the sound of a shadow demon shattering, and he was reminded of the war his brother had fought in. The demons who had murdered him for his bravery. He pulled himself to his feet, and laid all that was left of his little brother behind some crates, to keep him safe. Then he turned back with fury in his eyes. There was no one to hold him back now. Nothing to lose.
Howling he hurled himself at the demons, taking every burn, every gash, every broken bone. He fought till they were pulled into the sky by that glowing green light, and he fell to his knees, helpless, wanting something, anything to attack, to make pay for killing his brother. But there was nothing. Nothing, and no one. He managed to pull himself to his feet, was vaguely aware of some other hero, he thinks it's Batgirl, helping him to stand. She asks where Dove is. He gives a sort of snarl, but he's not really mad at her, not really, and makes his way back to Don's body. The body is broken, crushed. Don's face is relatively fine. But the blood slicked body in his arms hung limp, and he's torn and battered, crushed in a way the gentle boy should never be, and Hawk takes the remains of his cape and wraps it around the broken body; carries it away. Takes him home. Because there's nothing more they can do, and Hawk doesn't really care anymore.
He finds their house relatively unscathed, they live in the in a small neighborhood, so not really a target, and lays Don's body on his own bed, not yet daring to enter that empty room... Gently, he removes the suit as best he can, and cleans up his brother's body, before dressing him again, and sitting there. Staring at his face. At the face of the only person who really meant anything to him anymore. His life. If he focused on the face, he could pretend Don wasn't really dead. That he was just asleep, tired out after a long mission; exhausted, battered, sore, but happy, because they had saved the day, and peace had been brought about. He remembered the weary smile Don would give him, after a particularly grueling day, and his heart tore apart at the thought that he'd never see it again.
He reached out and cradled Don's face in his hands. Orphaned at ages 12 and 7, they had clung to each other, because they were all the other had. He had promised. Hank had promised that he would take care of his little brother, sitting by his mother's deathbed, father already gone; Don had clung to him, sobbing, begging for reassurance that it would be alright, that Hank would keep him safe. And he had. He had until a stupid shadow had taken his brother from him, until his brother's heroics had ended his life. Hank sobbed into Don's tattered chest. Don had been so proud when they had first saved someone as superheros. He had smiled so brightly, Hank had been forced to use all his control not to laugh with him, not to lose control and cheer with his brother. Don did that to him. And he was the only one who could.
Hank whimpered quietly; his place was with his brother. To be beside him, protecting him. Loving him. Now there was nobody to love. Nobody to ruffle his hair, and laugh the withering glare away. No one to hold him when he felt as if the world itself was at an end, like when the love of his life, Tiffany, had died. Don had known exactly what to do. He always would. He had taken care of Hank as much as Hank had protected him. He had protected Hank's heart. But now, he was dead. Dead. Gone. Forever.
He held Don had tightly as he could tighter and tighter, growing more and more desperate with every second, when he heard something snap. He released his grip fearfully, vulnerable, seeing seeping red when the bone had snapped under Hank's super powerful grip. Horrified, he laid Don down as with heartbreaking gentleness, whimpering as Don's head rolled limply to the side. He backed away from the body hehadhurthimhehadhurthimononononohowdarehehurthim. He pressed his back against the wall, heart crushed at the thought of hurting his brother, how horrible was he that he would do that to his little brother, his poor little brother…
Silent tears streaking down his face he ran from the room, but every room only served to throw the memory of Don at him, hurting him, and finally, for reasons he couldn't explain, he found himself in front of Don's room. He couldn't go in, he couldn't go in… he threw open the door. Everything was in it's place, neat and tidy, organised. Sobbing, he moved forward to the bed, throwing himself on top of it, smelling Don in every corner. He curled up on top the the blankets, holding himself desperately, shivering from a cold only he could feel. The silent tears continued, and he shook, arms wrapped around himself pathetically. Don was dead. Forever. His world was shattered, and could never be the same again. He lay there for hours, until the need to see Don overcame everything else, and he slipped from the room, and knelt by his own bedside, by Don's body.
Don didn't deserve this. Don was the most peaceful person Hank knew, the most gentle, the most caring. He died saving a child. Hank couldn't help but think that the child wasn't worth it. Because nothing was worth Don's life. Nothing. Nothing, and nobody. He wanted to touch the gentle face, to run his fingers over the short blond hair, just one last time, but he couldn't. What if he hurt him again?
His hand moved of it's own accord, hovering over Don's pale face. It stayed there, shaking, when he pulled it away, pressed his back to the bed, unable to control the tears that started anew. Finally he climbed up into bed beside his little brother, and pulled his remains close, but so gently, so very gently that he might as well have been handling glass. He stayed that way all through the night, knowing that soon, the one light in his world of darkness would be taken away, as it had already been snuffed out. He pressed the gentlest kiss he could muster to Don's unresponsive forehead, and buried his tearstained face in the crook of his little brother's neck. When he awoke the next morning, there was blissful confusion, as he wondered why he was sleeping beside his little brother, and why the little bird was so cold. Out of some prophetic instinct, he snuggled closer, and was confused when the felt Don's sides… an indescribable sound of pure pain made it's way from his lips, as memory crushed him to bits. He couldn't take this. Couldn't live like this. Don was his everything, the sun for his world. His galaxy. Sobbing, he stroked Don's hair, sat up and cradled the little body in his arms. There was the sound of cheering in the streets. The Anti - monitor must have been defeated. But cheering? When Don lay dead in his arms? Anger clouded his vision as he held his little brother tightly. He couldn't survive without Don. Not without his little bird. His gentle dove. He petted his brother's hair lovingly, as if to shield him from the darkness of the thoughts inside him.
"Don't worry." he whispered. "I'll be there soon. I failed you this time, but I'll take care of you again. Just you wait, my little Dove. I'll keep you safe. I'm coming."