Hi, my son has just about finished every Terry Pratchett book. He's a voracious reader and I need suggestions for his next read. He's a very mature 13 year old with a reading age more like 18, so I need exciting, funny and mildly complex books but ideally without too much sex. Probably not kids books as he's ready pretty much everything going. Doesn't have to be fantasy or sci-fi - I don't think specifically that is what he enjoyed about Pratchett, it was more the cleverness and humour. I had thought maybe some Stephen King like the Dark Tower perhaps?