Dean kept a close eye on Sam as he worked. Finally the were pretty sure it was down to an isolated farmhouse in Iowa. He could tell his brother was nearing exhaustion.
“Sam get some sleep,” said Dean, watching the house. “We’ll hit it at dusk.” He checked his gun and sat down to keep watch.
“…I’m going to gut whatever did this,” Sam said vehemently, though his eyes were starting to close on their own. He slid down in his seat, resting his head against the glass. “Hang in there, Jack. Just a little longer."
He was asleep in minutes.
The house stayed quiet as Dean watched, trying not to think about what could be happening to Jack inside. But if they went charging in they might all get killed, and odds were Sam and himself wouldn’t come back. He suspected Jack wouldn’t forgive himself for getting Sam killed, mostly because he felt the same way. Whatever was between Sam and Jack, it was special, even he could (stubbornly) admit that.
Finally he judged it was late enough. He checked his gun and glanced at Sam’s sleeping form, worry pinching his features even in sleep. He shook his foot. "Come on, let’s move.”