I'm sorry, I couldn't find any information about an author who wrote his last novel in crayon. It is possible that this is a fictional story or a reference to a specific work of fiction that I am not aware of. Writing a novel in crayon would be a very unusual and difficult task, as it is not a traditional medium for writing and would be difficult to read and preserve.
In literature, there are many examples of authors who have pushed the boundaries of what is considered to be a "traditional" way of writing, but I couldn't find any information about an author who wrote a novel in crayon.
It's worth noting that writing a novel in crayon is not a practical way to write a novel, and is considered to be a very unconventional way of writing.