We were all avid readers in my family except for my brother, who was not keen at all. He was into fishing, and so we got fishing magazines and he also liked going on his bike. Just cant remember the name , but we found a nonfiction book of someone going on a long journey, not round britian but that sort of thing. This was 50 years ago so not a lot of marathon things going on at the time. These worked well and did encourage him to go into the library and have a look round.
So I think a two pronged idea is to see if you can find some audio books that he would enjoy. He should feel very relaxed about them as he is not struggling to read them , as he sees it. But it will be broadening his vocabulary and this may also encourage him to get another book from a series as he will be familiar with the characters, which he could read himself. He will understand the overall scenario and therefore will be able to "guess" a word that he does not know from the context. Then hopefully he will feel confident when he has read that well and will be prepared to try something else, building on that success. I think it is world book day today so a great time to buy him a paperback as a treat. I think Adrian Mole might still be a possibility and definitely Wimpey Kid series are very popular. Perhaps you might also go in reverse, by have a DVD of astory or going to the cinema to watch something that is based on a book and then he could get the book from the library and with his knowledge of the basic story would probably be fine reading the book and having educated guesses at words he is not sure about. The success of getting through it is a good boost to his confidence. Making sure he has a library ticket and the opportunity to go there easily on his own, where you might have a quiet word beforehand with the librarian about helping him find the sort of books he could enjoy. Good Luck, I personally think encouraging someone to become a good and happy reader is a great gift for life. It has certainly been important all my life and still is one of my greatest pleasure, that is available to me at any time day or night, and gives me information, pleasure, solace and joy at very little cost. So a gift for life that was encouraged by my granny which I treasure.