Sorry for the unoriginal title, but it was written for the prompt: he ain't heavy, he's my brother. Reviews are my crack.
Damon had many scenarios in mind for when he found Stefan but this certainly wasn't one of them.
He was following another lead he had gotten, but his leads only led to one of two things: a dead end or a clue to where they might be now because they were already gone. The abandoned house was the same as always after Klaus left. It looked like a horror movie: blood everywhere with some corpses lying around. The difference today was the dead bodies was more undead than dead.
Stefan lay in the middle of the floor in the fetal position. Damon rushed to his side. "Stefan? Stefan?" he shook his brother's body.
Stefan looked up, his brow furrowed. "I killed them. All of them. The pain. They screamed. So much screaming, Damon."
"Stefan? What's wrong? Are you hurt?" Damon asked. He couldn't see anything wrong with him. Sure, he was a little beat up, some cuts and bruises, one particularly bad gash on his side, but nothing that should incapacitate him to this extent.
"No I hurt them. Don't you get it? They're all dead because of me. I have to pay. She said I have to pay."
Damon gripped his brother's shoulders. "Stefan, who is she?"
"Witch. She told me I have to suffer."
"A witch? A witch did this to you? So it's all a spell," Damon concluded.
"Their voices are in my head. I can hear them all tell me how I ruined their lives, their family, their everything."
"C'mon, get up." Damon started helping Stefan to his feet.
"They're all in so much pain, Damon. We cause pain." Stefan was weak. He couldn't stay up very well.
"When was the last time you ate something?" Damon asked as he put an arm around Stefan's waist to help keep him upright.
"You don't even understand what we do to them."
"Stefan! Last time you drank blood? When?" Damon demanded in a loud tone.
"Weeks ago. She was a witch. She didn't want to help Klaus."
"And he made you try to kill her."
"I didn't kill her…..the voices, Damon. They're so loud."
"Don't worry. I've got you now," Damon said as he guided Stefan to the car. "I'm gonna take care of the voices, okay? They'll stop soon. Bonnie will get them to stop."
"The voices said you wouldn't help. They said you finally got everything you ever wanted."
"The voices don't know shit. You're my brother, and I'm the only one that gets to drive you insane and try to kill you. Not some pissy little witch."
"Damon…" Stefan trailed off.
"Hey, you're gonna be just fine. Watch your step," Damon said as they went down the two stairs from the porch to the ground. "We're gonna get you some help. Till then, try not to bleed on the interior of the car."
Later, after Bonnie helps Stefan and he is off being cared for by Elena, Alaric asks Damon, "Why did you help him? A little while longer and Elena probably would've been yours."
"He's my brother. While having him lost in the middle of Mississippi, sitting in his own filth with no intention of ever leaving would be convenient, he's still my brother."
"Watch out," Alaric says, "People might start to think you there's a heart inside your cold, dead chest."