Richard Griffiths (Vernon Dursley in Harry Potter) spoke about Daniel in the upcoming play Equus. This is what he said:
"The role is a 17-year-old boy, which is essentially what Dan is. So, from an acting point of view, all he has to do is behave. The boy has no awareness of his emotional impact, so you don't want acting - you want natural behavior. I'm confident Dan will do well."