score:3
Typically, in the United States (I am not sure which country your friend's passport is from), there is not a problem so long as the chip is working. I'm confident that is the same in Europe, as I've traveled throughout with what you're describing. [I hold a USA passport with a work visa in the UAE]
However
When I took the same, worn passport traveling to other countries, it caused a lot of trouble, even though the numbers, the photograph and the bar code were both legible, and the chip works.
My very strong recommendation is to have your friend get a replacement passport just to avoid the unnecessary hassle if someone doesn't like how worn or 'suspicious' it looks. The minute I got back to Abu Dhabi I went to the US Embassy, got a replacement, and haven't had a problem since.
So she might not have a problem, but it's probably not worth the risk.