Sounds like an interesting student. I guess he has spent a part of his life living in an English speaking country hence the implicit knowledge of English without the explicit knowledge.

You are probably best looking at the books that Cambridge publish themselves or at least the list of books from well known publishing houses that they also list on their website.

http://www.cambridgeesol.org/exam-preparation/books-study.php

If it is just the 'Use of English' section you are worried about then you can download some example exam papers. A lot of the books on that list are in essence just a big mock exam, however you can also download past papers from the Cambridge site and other places on the internet for free.

You might also consider a standard grammar book like Swan - Praticial English Usage. It's fairly easy to digest in comparison to some other grammar books