Castiel had initially planned to stick around and monitor Sam's condition, as the angel seemed to be more aware of other possible symptoms that could develop with the mark. He also wasn't completely sure the caster's soul wasn't infected, though he hadn't shared that piece of information with his friends; sometimes the soul a caster that desperate would fester, especially if that wasn't their first soul-rending spell. A wounded soul rarely healed well. Until those symptoms developed, however, he didn't want to worry his friends with the possibility. And after a day and a half of Dean's stressed sarcasm, Sam's non-committal responses, and no change in the mark, Cass decided that he would be put to better use researching…..outside the bunker. Sam followed him to the door and apologized briefly for Dean, who hadn't even looked up when the angel had announced his departure. Cass waved him off.
"Call if anything changes, please." He said, looking intently at Sam. Sam sighed, realizing Castiel could probably read him about as clearly as his brother could. The thoughtful looks he had been receiving over the last day made him wonder just how much the angel had noticed. "And be careful."
"I promise." He offered up a genuine smile that almost concerned Cass. The younger brother seemed confident that he had already resolved the problem, though he hadn't shared that solution with the rest of them. "You too." The angel gave Sam a meaningful look which was brushed off. And with that Cass took his leave.
Three days later, Dean had hardly left his seat. Bags weighed heavily underneath his eyes, which had faded from their normal vivid green to a pale green-grey. While he had showered and changed at least once since taking up his post at the research table, the constant burden of his worries kept him looking washed out, rather than clean. He was determined to find a way, some way, to reverse that confounded spell, or remove the soul, or just transfer the damn thing to his own neck so he wouldn't have to worry about what it might do to his brother anymore. Sam didn't seem to be showing any adverse symptoms so far, and Dean wanted to keep it that way. He was afraid that if they just left it as is, with the trigger unknown, that one day he would turn around and find Sam lying on the floor, cold and stiff. Whenever he shut his eyes that image danced in front of them, warding against any chance of restful sleep.
Sam was just the opposite; he couldn't seem to bring himself to care about the mark. It had actually stopped hurting for real this time, and hadn't expanded since the night they had returned from the hunt. After the first night of fitful sleep, Sam had taken the research pretty seriously. But after finding that passage in the book, and after deciding to limit contact with his brother, he found himself apathetic about the mark. As long as it didn't act up, there were more important things to focus on. After deciding that, he had had the most restful sleep in years. Now if only Dean could do the same.
Pretty sure his brother was somehow linked to the spell's trigger, Sam wanted to find something, anything else to occupy his brother's mind. For all Sam knew his obsession over the thing WAS the trigger. But he couldn't just say that to Dean; knowing his brother would start blaming himself for Sam's mark, and Dean didn't need to wear any more guilt than he had already forced on himself. In an attempt to distract him, Sam had found a couple of possible cases in the nearby states; but Dean had barely given them a second glance before returning to his reading. Sam had to admire his dedication to the research. He read almost as much as Sam usually did, though Dean insisted that was an exaggeration. "How could I ever reach your level of nerd, Sam?" He had offered once with a light-hearted smile. Sam had been glad just to see that, brief as it was.
A week passed, and finally Sam had had enough. Dean looked like a walking corpse, and now refused to even leave the table. He had been reading the same paragraph for three hours, but kept insisting that he was almost on to something. Sam really wanted to clock his brother on the jaw and knock him out cold, but after Dean's concussion from the last hunt he didn't want to add any additional damage. Instead he took a dose from his stash of sleeping medication and dissolved it into his brother's coffee. Sam was thankful he had decided to sneak some from the pharmacy where they had worked a case a few months ago. He laughed at the memory; they were hunting a junkie turned werewolf, who despite being unable to feel the effects of his old favorites had continued his habits, and in a fit of desperation began robbing local pharmacies to try and get his fix. Ironically, he had been strong enough to resist the urge to eat hearts for months, so focused on his drug problem's problem instead. The only thing that had given him away were the constant sightings on the lunar cycle by the overnight janitorial staff. They caught him easily, his arms so full of opioids he couldn't even run. Sam almost felt bad for the guy, but knew a monster that unstable was nothing but dangerous.
Although Dean was usually pretty good at detecting drugs in his food, his sheer exhaustion prevented him from noticing, and within about half an hour he was sleeping soundly on the table. Not quite satisfied, Sam tucked Dean's arm around his neck and hoisted him out of the chair, awkwardly carrying him back to his room and thankful for once that Dean had insisted on having the room closest to the door. Dean's head lolled gently on Sam's shoulder. As Sam sat him down on the bed and lowered him onto the pillows, he mumbled Sam's name, clearly worrying over his brother even in his drug-induced sleep. Sam let out an exasperated breath and smacked Dean lightly on the forehead, not enough to wake him, but hopefully enough to refocus his thoughts for the night. Dean quieted, and Sam wondered with a quiet laugh if it had actually worked. He exited the room without ceremony, muttering a passing, "g'night, Dean," as he pulled the door shut behind him. He tried to ignore the warmth Dean's arm had left on his neck.