I used to recommend The Big Bag of Worries by Virginia Ironside, although I suspect it covers much of the same ground.
I have long been a fan of 'fantasy' books for older children / young adults, as they can see the world from another perspective, and how people find strength in difficult times.
If he hasn't read them already, then I think Harry Potter would be ideal, and the Wizard of Earthsea series. There has been a recent film made of one I loved as a teenager A Wrinkle in Time.
The Percy Jackson series by Rick Riordan, are aimed at children with conditions like dyslexia & ADHD, but are also popular with those who feel a bit 'different'.