I wouldn't consider the owner's friend's review to be "fake." As for the owner him/herself, that might feel a bit unethical, but I still wouldn't call it "fake."
So while you might not consider such a review as fake, my understanding is that the FTC would.
I would. If Obama wrote a book and his childhood friend reviewed it on Amazon, I would discount that review. Or at least consider it highly suspect.
To me, fake and biased are not too far apart considering the context that I expect reviews on books, restaurants, etc. to come from random people who don't have any particular reason to like or dislike the product outside of the quality of the product itself. I believe friends & family are too close to the product to give a review without external-factors influencing. It's true that the friend could have truly enjoyed the product, but I still think the chances that their review was influenced by their friendship is high enough to make the review suspect.
The problem with that expectation is that voluntary reviews already self-select for people willing to write reviews, which will almost certainly introduce strong biases.
But, I guess that's the best we've got, right? Otherwise how do we go about getting reviews for anything? I definitely think forcing people to do reviews that they didn't want to write would produce mostly garbage.