Most of here can testify to what your friend has said. It's very close to the events in the book, sometimes the dialogue is even lifted from the book, word for word. The latest episode contains the most original scenes that aren't found in the book, but it's a testament to the writers and producers that the new scenes don't feel out of place at all. Some of them are there for exposition (Like Tyrion's discussion with Theon Greyjoy or Sansa's history pop quiz) that you could only ever find in the book, which is understandable, but some go some way to better explore the characters (Jon's conversation with Sam while cleaning the mess hall) probably because it's a lot easier to write out what the characters are thinking in the books, but not so easy on TV.
The only complaint I see from most people is that there's not enough time given to the direwolves
It's understandable, they're meant to be bigger than most wolves at the time so I imagine the filming logistics of getting a wolf to behave whilst the actors are doing their thing, or even the CGI costs to make them slightly bigger in size would be just unnecessary. I'm not fussed. In fact, you know that when you do see them, it just makes it that much more awesome.