"N is for Neville who died of ennui"
There is nothing very deep of this child, at first glance anyway, but really goes farther than that. Yet, let's look at it like this, with a boy, named Neville, just bored with life, everything up to his short life span, nothing appeals to him. Everything around him can entertain him, for nothing longer than an hour.
Nothing pleases this boy, nothing else in on this green planet, even if far back to his timeline. There was not a toy, a treat, a show, or even a board game, could keep this boy alive with a smile. Having this odd sickness, known only as ennui just drains Neville away until he's just skin and bones. Neville likely born as a healthy boy, never took drugs, his mind was set forward to see thing go.
To everything though, he just lost interest in things, which were seen as normal to children his age. Neville should go out and play, stuffing his face silly with sweets he sunken around when his parents weren't looking, pulling pranks. Something, anything really, that didn't involved looking out a window. With a face so still, that if no one caught him blinking or breathing, some would think he was long gone.
Maybe, they are not far from the truth, it fits in certain ideals?
Could have been a chance, the parents thought he was normal, but didn't bother to noticed the slight different human reactions, out of that; he was just being his own human?
The perfect golden child, wasn't what they said he was, only doing so, to keep away nosing sneakers out?
The risk that knowing Neville could be at, with having a mental break down, and having no one foretaste it?
Having this child, stay there by the window, with the coldest and stiffest face there ever was. Eyes just glued to the emptiness of the outside world, where even the window, doesn't give enough to emote something from the boy. Just sitting there, letting his body shut down, from pure boredom. In hindsight, it doesn't sound like a sickness to die from, yet little Neville found a way, unknowingly with bleak eyes, begging to scream.
Though, still Neville remains where he sits, until his heart also gets bored with him. Forever and to never waking up, not matter how interesting even in seeing the rising sun could do to bring him. It did not.