"As a rule, I don't bring people back. I might make an exception once, not twice. So… Pick."
Death had a reputation to uphold, but that didn't make him a heartless monster. When he gazed upon the cage, he recognized it as a dungeon designed specifically for a fallen angel, not two children. Besides, Lucifer was far more arrogant than the eldest Winchester, which was not something Death could simply forgive. And so, like a gentle, loving father, he welcomed the boys into his arms, returning Sam to his brother on Earth… before delivering Adam to his mother in Heaven.