The brothers' relationship hasn't been perfect since Dean showed up on Sam's doorstep to drag him back into the hunting world, but everything in Dean's life seemed to have a bit more color with his brother by his side. He hadn't realized how lonely he was until he had someone to bitch at, someone to listen to classic rock on long road trips with, someone to face all the monsters lurking in the dark with. Someone who had his back, no matter what, and he had his. But he'd be lying if he said it didn't come with a whole lot of guilt, and a whole lot of worry, especially since Sam had started having nightmares that seemed to be premonitions. Despite Sam trying to play it cool, Dean could tell he was scared of what was happening to him, especially given what it had already cost him. And even though he'd never admit it, Dean was scared for his little brother too.
At first glance, this current case didn't even look like a case. But Sam was fixated on his nightmare, so they were holed up in yet another sketchy motel room trying to brainstorm what could have killed a man in what looked like a pretty clear suicide. Dean was trying to gently push Sam towards the realization that there was nothing there for them, but Sam was convinced something was wrong and wouldn't budge. Sam had been pacing the room, trying to shake some new thoughts loose, until he finally came and sat on the bed next to Dean's. Cleaning his gun, Dean didn't notice a problem until he heard the cadence of Sam's speech change, the tone of his voice growing strained. It was then he looked up and did a full double-take when he saw Sam's hand pressed to his head, his face contorted in pain.
"What's wrong with you?" Dean asked, trying to sound casual even as his heart was starting to race, even as dread started to rise in his gut. The gun he'd been cleaning slowly lowered onto the bed, forgotten.
"I – my head," Sam choked out, falling to his knees on the floor.
"Sam?" Dean asked, fighting back the panic in his tone. Every sense heightened, Dean was on his feet in an instant, moving to kneel in front of his brother and grip him by the shoulders. Sam was grinding his teeth, hissing in pain, trying to catch a breath but managing little. The only sound in the motel room was Sam's ragged breathing, his occasional cries of agony, and Dean's heart pounding in his ears. "Hey. Hey! What's going on? Talk to me," Dean pleaded, to no avail. Sam finally stopped grabbing at his head and reached a hand out to fist in Dean's shirt, but gave no other response. A look of fear overtook his features and his pained gaze turned into a thousand-yard stare. Though Sam was physically present in the room, it was clear that he was mentally elsewhere, far away from where Dean could help him. "Sammy? You're scaring me, man. Come on." Dean tried to take a casual tone, but when Sam didn't even react to the nickname, the icy terror started to move in faster. His brother was frozen, unmoving, holding onto Dean for dear life. His breaths were irregular and sharp, and his eyes remained locked on everything and nothing all at once. "Sammy, man. Breathe. Come back to me," Dean ordered, searching Sam's gaze for something, anything. He kept his hands on Sam's shoulders, rubbing one hand back and forth in an attempt to ground Sam from whatever was trying to pull him into orbit.
Panic attack? Absence seizure? Angry spirit attack? Stroke? None of the options were good, though some significantly worse than others. Dean didn't have any information to narrow things down in any case. He didn't want to call 911 unless he had to – and besides, his phone was across the room and he wasn't leaving Sam like this, even for a moment. But he couldn't move his brother in this state, either. So he sat with Sam, whispering quiet reassurance and reminders to breathe, unsure if Sam could even hear him or process his words but needing to say them just the same. Time passed for what felt like hours but he knew was probably minutes before Sam flinched forward, off-balance on his knees, and Dean steadied him. Sam seemed to snap back into his body in an instant, finally meeting Dean's eyes. That alone loosened the vice grip around Dean's lungs enough for him to get a full breath.
"It's happening again, something is going to kill Roger Miller," Sam choked out, frantic, already trying to stand. Dean kept his hands locked on Sam's shoulders, pushing him back down as he started to sway on his feet. Even back on his knees, Sam was unsteady, and Dean took the bulk of his weight.
"Whoa, whoa, whoa," Dean murmured, holding his brother in place as Sam shook in his arms. "We'll go, but after you take a second to breathe, all nice and slow-like."
"Dean, we don't have time," Sam tried to protest, his eyes filled with sheer desperation and panic.
"You're no use to anyone if you pass out, Sam. Breathe for a second," Dean retorted, harsher than he'd meant to. His heart still racing, he took exaggerated breaths and instructed Sam to copy him. It got the point across and earned him about 30 seconds of Sam taking deep breaths before moving to stand, much more slowly than before. He was still shaking, though much less noticeably than a few minutes prior. Dean hovered behind him the whole way to the Impala, and tried to steal inconspicuous glances over at him as they started the drive and Sam found the address. As much as Sam tried to pretend he was fine, he was still grimacing in pain every few moments.
"You okay?" Dean finally asked, after suppressing the question as long as he physically could. He knew his tone was almost angry, but any smidgen of control had flown out the window when his brother had gasped in pain and gone unresponsive.
Sam reassured him that he was fine, at least physically. Dean knew that he would, even if he was on death's door, but it helped soothe him just the tiniest bit. Until the next thing out of Sam's mouth was that he was scared. Dean couldn't remember the last time he'd voiced any of his fears aloud, any time he'd felt safe being vulnerable. A wave of protectiveness crashed over Dean, just like when they were little and he had to help Sam through a fever, a nightmare, a fear of the dark. So, even when asked point blank, he lied to Sam's face and told him he wasn't worried. And to Sam's credit, he didn't call his bluff.