[governsleastgovernsbest]

"The primary use is to indicate that what preceded it was the text exactly as found."

ABC had put the friend's statement inside quotation marks. So it was already clear that the quote was verbatim. The only purpose of the 'sic', therefore, was the second one you offered: that any error was that of the original author, not of ABC.

[aruanan]

ABC had put the friend's statement inside quotation marks. So it was already clear that the quote was verbatim. The only purpose of the 'sic', therefore, was the second one you offered: that any error was that of the original author, not of ABC.

No, even when quoting, the sic can be used to show that the quote is exactly as found.