I didn't encounter him directly admitting it, but I was really tickled by the post-credits scene as that was when it finally clicked for me, even though there was lots of foreshadowing. I rather like the idea of it only being revealed post credits. it reminds me of Solas' final scene in Dragon Age: Inquisition which has a very similar vibe.

Could the post-credits scene be a teaser of things to come in Baldur's Gate 4, assuming that will be a thing. (It had BETTER be a thing!)