In the series, Sam believed in the Easter Bunny till he was eleven and a half. Does that mean that in the ba universe he stills believes in him?
Aww! The poor kiddo missed out on a few human experiences the rest of us have to deal with.
Of course, just because he didn’t have Dean around to break the bad news to him, doesn’t mean he didn’t learn the truth. He’s not separated from humanity like Asunder Sam was, and they do pick up a lot of gossip from the human chatter in nearby rooms, along with what’s on the TV.
Walt never really understood why humans needed to believe in giant bunnies that brought them candy and probably shattered Sam’s world with an offhand comment about it one day. Dean would have been in stitches to see Sam’s face.