LondonFA:
How do you respond to reading erotica?
If your own imagination of erotic moments bring arousal and further to that, stimulated visualisation by reading and imagining erotic moments cause you to be aroused, then it is unlikely that you are asexual.
That's simply not true. Asexuals can be turned on by all those things, they just don't have any innate drive to have sex. For example, someone writing about someone getting fatter can turn me on.
If not including grey asexuality, then by the definition of psychological asexuality he does not by his description demonstrate sufficient trait to be defined as wholly asexual and under definition should not be categorized as such.
Understanding that psychological terminology is not always how terms relating to sexuality are used inmodern online parlance, I assume that you are implying that he may wish to explore the idea of being in the grey scale.
This isn't a bad thing, but again given his wish to have sexual relations and that he simply doesn't enjoy graphical pornography, I fail to see the evidence for your response. Please elaborate if you have time.