I would stay away from books that are just page after page of logos. They are often (not always) just about the latest trends and encourage copying rather than understanding why they work. Logo design and branding is much more than this. You want something that helps your friend develop.
David Airey is a pro when it comes to logos. Take a look at his site (Logo Design Love). He has a list down the right side with some personal recommendations. I've got Marks of Excellence and would recommend it, but it is a little dry.