Please help me identify a book

This question was posed by a client. Although I haven’t read this book, I am sure I have read a review of it. Does this sound familiar to anyone?

I believe the title is an one word portmanteau-ish term. I think part
of it may include “artist?” “human?” I read this in the late 1990s to
2000s.

It’s about a social worker (male) who to his disbelief discovers an
idiot savant (male) with an amazing creative artistic gift. The social
worker is further incensed by the man’s sheer joy in the creative
process.

I believe they first met on the steps of the Met in NY.

The social worker then proceeds to gain control of and experiment on
this man to see what would happen to the man’s gift for art if
deprived of both stimuli and the means of expression. Ultimately the
social worker locks up the idiot savant in an empty room and starves
him to death.

The book turned out to be The Nihilesthete.