Remembering Hiroya

Attention Hiroya fans!  The wild-haired eccentric Japanese painter Hiroya made quite an impression on this Japanese woman when she bought one of his paintings in 1997.  Now she would like to know more about Hiroya and would like to get in touch with others who share a passion for his work.  She's also curious as to what kind of person now inhabits Hiroya's room.  Speak up, ya'll!  She also told us that she's reading Florence Turner's 1987 book, At The Chelsea, which is available in Japanese!

My name is (redacted). I am a Japanese woman. I sent this e-mail to ask something about Hiroya.  I have stayed at the Chelsea hotel when I visited New York in 1997.
At the stay, I met Hiroya and I bought his painting.  Although I talked with him little, I have remembered him for this 10 years, maybe because of the strong impression of him and his room.

Recently, I got to know by hotel chelsea blog that he died. If you know why he died, could you let me know? The blog also said that Hiroya went to rehab program, what does rehab program mean?

I just want to know about him because I think I am responsible to know the person who painted the painting which is still on the wall of my room.

Hiroya is unknown in Japan. That's why I could hardly find his name in Japanese search engine.  I want to know how many Japanese tourists bought his paintings as I did, but I have no way to know it.  I also want to know his profile or his life if I can.
Are there any hotels or galleries that still keep his paintings except for hotel Chelsea?
What kind of person lives now in the room where Hiroya lived?
I am kind of an illustrator now.
This has nothing to do with Hiroya but may be the reason why I am attracted by him.