There’s no plans for him to meet Bowman and the earthbound sprites just yet, at least not in the original Brothers Apart series, but there’s always the possibility he’ll show up in another AU and see the sprites. I think it would be most likely to happen in Brothers Asunder, when Sam’s fate is more closely entwined with Bowman’s as his adopted little brother.
An Appreciation for the Sun was a really fun time! I’d definitely be willing to do something like that again, as a collab or on my own (I have some Cas prompts in my inbox that I’ve been mulling over).
The sprites would be so intrigued by his wings. I can see them fluttering around behind them after he’s shown off the shadow and getting confused. They’re not there? But they saw them a minute ago? How are you doing this. And his healing would definitely be impressive. It’d be like the Spirit Herself’s healing, so fast.