The following meaning is from a smaller copy of the Oxford English Dictionary,eleventh edition,2004, than the compact version I used previously and this is the only definition given; (after a copied or quoted word)written exactly as it stands in the original. - Origin L.., lit. 'so, thus'.
The usage is certainly not archaic.
Furthermore, providing proof isn't incumbent upon me. The proof is required of the one who made the initiial charge that I questioned. I'm not seeking to prove anything, only to offer a plausible explanation that might disprove the charge.
Argh. You just refuse to understand. YES, sic does mean "written exactly as it stands in the original." But it is only employed when the reader might otherwise think that the transcriber had made a mistake. It's the transcriber's way of saying: "I didn't make the mistake; the original author did."
In the current context, it's ABC's way of saying, "yes, the friend really did say that he'd see SPC Donica again, as odd as that sounds."