Yeah if you go into any good bookshop, or WHsmith you can find many guides for almost any subject, however they can be quite pricey
www.bbc.co.uk/education/asguru is a really good site if you don't want to splash out on expensive guides,good luck to him in his exams
Try Amazon and Ebay. Sometimes AS study guides are very cheap. (Amazon has a fixed postage charge of �2.75, which is high for a study guide. Ebay is sometimes cheaper)
These ( STUDY GUIDES ) will give you a summary of the book, character analysis, plot and much more, so that you will be able to answer literary questions.