Alexis was delirious with exhaustion, having been up for nearly twenty-four hours at that point, and as such, she wasn't paying attention when she walked into Beckett's room and practically ran into her father.
Hunched over Kate's supine form, Castle's shoulders were shaking with sobs, soundless and agonizing, his hands clutching at the blanket draped over her knees.
She didn't know what to do. She was horrified; in sixteen years, she'd seen her father cry once and at that time, all the nine year old Alexis had known to do was stroke his hair and catch his tears.
Castle collapsed into his daughter's lap immediately when she perched on the edge of the bed. He twisted the hem of her jacket between his fingers and rested his forehead on her knees.
Alexis swallowed the lump in her throat and gently shushed him, running her fingers through his hair.
"It's okay, Dad. She's going to be fine."
He shook his head, his words getting lost in deep, shuddering breaths.
"Daddy-"
"Alexis, I swear, if she wakes up," he breathed, wiping his eyes. "If she wakes up…"
"I know, Dad. I know."