So far it's mostly about John, but there've been glimpses of um, what's the opposite of flashbacks? flashforwards? set later exploring Sam and Dean's reaction to John's hunting lifestyle when they are older, e.g. in the first issue was a short backup story about Sam and Dean as teenagers, and the events of the third issue are framed by a sequence taking place 1991. But so far we don't see much of them. Though we do see some effects the hunting has on little Dean, like his reaction to his John moving them and leaving them with others, and in the third issue he sees John shooting a shapeshifter (who looks like one of the hunters with whom John went since that is the form he took) and is further traumatized by that.