I'm probably not the friend of a friend you're talking about but I've asked confident, articulate people to solve fizzbuzz and similar toy problems many times, only for them to fail hard.

Nowadays I tend to use such problems as pre-screeners in a short telephone interview[1] before inviting candidates to attend a full face to face interview because it saves wasting everybody's time, including the candidate's.

Sad but true.

[1] We use codeshare.io or, if it's oversubscribed, Google Docs. Massively prefer the former because it includes syntax highlighting and support for many different languages, so it feels much more like a decent code editor. With Google Docs you're using a word processor which is far from ideal for many reasons, including that you feel like you're fighting autocorrect the whole time.