From what I hear, Amazon is incredibly uneven in org quality, so it is really possible your friend got unlucky. My wife works at Amazon and seems to have a pretty good balance and has good things to say about her work environment, but she is not a SWE (rather a designer). Still, I don't think I would ever work there without a lot of careful research about the group I was going into.
> When you’re a candidate you are rolling the dice
Ya, and the recruiters always try to get you into what sound like would be the worst orgs (I would guess positions in good orgs are "known" about outside of what the recruiters are trying to fill).