There is literally no other corroboration that could be given, it’s a personal conversation between friends or friendly acquaintances, reported as such. There’s nothing wrong with the article. This is the maximum amount of corroboration for a private conversation (none) and it’s reported as a conversation, with information about the speaker’s relationship and direct quotes. Just because people don’t record their lives in unalterable write-once media doesn’t mean personal conversations simply should never be the subject of reporting. We have headline news stories about US generals’ personal conversations with Trump and his denials, and no one thinks “well, that shouldn’t be reported because either side could be lying and without recording they’re both equally suspicious”.
I’m certain you don’t actually follow a philosophy of “nothing anyone says can ever be given any more credence than anyone else” because it’s an impossible way to live. And whatever high-minded “no one can ever know absolute truth” ideas you have, claiming that a HR rep and a family friend have the same level of believability is ridiculous. On one side you someone whose job is literally to say things to protect a billion dollar company and the other a family friend with nothing to gain talking about a pretty reasonable conversation one might have.