This has all been one been creation by Neko all along! As I figured after this episode, we also get her ED back. Well I didn't really expect her to be the reason for everything in the series. If she really did just find Shiro lying there and didn't know anything, perhaps her role has been served in terms of the plot, and now we have to find out what Shiro's story was before she came along and made a life for him.
Avatar: Tomoya Okazaki from Clannad/Clannad After Story (courtesy of Jun Kuga/Fudce from The Fandom Post)