This idea came from a fic I read called, "More Oniichan" by BakemonoShoujo
"Daddy.." Rin groaned. He laid in bed with a whimper, his cheeks expressing a red color that indicated that he had a fever. He had tears in the corners of his eyes. Rin was sick.
"I'm here, I'm here," Shiro said. He sat beside his bed with a bucket of water and a cloth. Shiro wet the cloth before wringing it out and gently placing it on Rin's forehead. "Daddy will make you all better,"
Yukio stood close next to his Father. Clad in only his pajamas and classes, Yukio wanted to make sure his brother was alright. The two had always shared a bed, though were separated for the time being so that Rin wouldn't spread his cold to his twin.
"Yukio, why don't you go to bed?" Shiro suggested as he stroked Rin's hair lightly. The older of the twins had shut his eyes as he rested, breathing heavy breaths through his mouth. His nose was as pink as his cheeks were, and the rest of his skin was paler than usual.
"I wanna stay to make sure Nii-san gets all better," Yukio said firmly. For a five year old, he was being very stubborn. Something he usually wasn't. Though, it was coming to his older brother. Someone he loved dearly.
"Alright," Shiro chuckled. He patted Yukio on the head and sat the boy on his lap as they watched Rin. Rin had fallen asleep, though eventually woke back up, not as they would have expected.
"Are you God?" Rin asked, blinking with his eyes wide. Shiro raised an eyebrow.
"What?"
"What's the neighbor doing here?" Rin asked suddenly. Shiro gave a sigh. "Where did my moley brother go?" the elder man couldn't help but give a chuckle. He watched Yukio frown and began to whimper.
"It's not my fault I have moles!" Yukio exclaimed with a quivering voice. He whimpered once more, clinging to his Father.
"No, it's not," Shiro chuckled. He realized Rin must be getting delusional from his fever. "Calm down, Rin, your brother is right here," the man said as he patted Yukio on the head.
"..Moles.." Rin whimpered before he fell back to sleep. Shiro decided it would be best if Yukio went to bed. Who knew what else would sputter out of Rin's mouth to offend the teen.
"Let's go to bed, Yukio," Shiro said. He lifted the brunette off his lap and carried him to his own room. Since Yukio shared a room with Rin, Yukio would be sleeping with Shiro for the night. "You stay here, and Daddy will be in soon enough. Alright?" Shiro smiled softly.
He exited the room and walked back to Rin. He would keep an eye on him for just a little bit longer before returning to his own room.