I've been on DA for years. Its in the nuance of how they type. Kids would usually type shorter sentences, plus their faves are clearly fetish-based. Younger kids on DA tend to fave a mishmosh of art from titties to cool art to maaybe some fetish stuff.
Profoundly autistic adults are completely aware of their fetish and seek out art of it, as seen by his posts, stating he wants a wedgie spanking fetish roleplay, and his faves are full of fetish shit.
Like I said, a waste of a life. You can read his life story in half a minute scrolling his DA, and I admit it was a waste of half a minute.