 Going by the name "Emanuel", Castiel used his powers to heal people, though he didn't know where that ability and his power to see demon's true faces came from.After Sam is committed to a mental hospital as a result of the hallucinations of Lucifer he is suffering due to Castiel breaking his "mental wall", Dean searches for "Emanuel" and kills a demon that is holding his wife hostage.Castiel agrees to help Dean who doesn't tell him who he really is, but mentions what "Cas" had done to Sam.