Sam leaned his head against the glass window of the passenger side door and gritted his teeth. The impala hit a bump and Sam's forehead smacked against the glass with a dull thump. He lifted his head up, leaving a smear of oil on the glass.
Dean shot him his usual surreptitious glance. "Dude. Clean that grease smear off later."
"Yeah." Sam replied dully.
Dean lifted his eyes at the tone, his expression suddenly sharp. "You okay?"
"Stomach ache."
Dean sighed. "Flu?"
"Dunno." Sam replied with a slight edge of pain to his voice. "Think it's bad diner food."
"You gonna barf? If you're gonna barf, do it outside my car." Dean's tone was breezy, almost dismissive.
Sam cleared his throat. "Not gonna barf," he said miserably.
"Uh huh." Dean replied, clearly not convinced.
Sam's jaw had gone tight and he was breathing through his nose in short puffs.
Dean swung off the road with a sigh.
"What are you doing?" Sam asked.
"Giving you time to rest. Go lay in the back."
Sam was about to protest but stopped. He understood the unspoken short hand. He understood what his brother was saying: it's okay Sammy. I'll take care of you.