YA Sci-Fi Mystery. Disabled boy on a space station. Scientist who always smoked cigars, he dies... Read mid 2000s. Spoilers.

[Aaron]

I'm looking for as I recall a Young Adult Sci-Fi mystery that I read in my school days. A young boy on a space station, as I recall he had some type of disability, there was a scientist who was always smoking cigars, scientist dies, his assistant is understandably shattered, then at the funeral he realizes the scientist isn't dead and nobody believes him until he goes "Where are the yellow stains on his hand from his smoking? They're not there"...and then somebody shoots him out in an escape pod and leaves him to suffocate. The end tying up of the plot involves cloning. The dead scientist wasn't the real deal, it was a dead clone. I read this in I believe the mid '00s, prior to '08 when I was definitely still in school. I can even remember the cover with the space station on it...tearing my hair out over this one. Was searching for another book earlier and found it with some Google-Fu, no luck on this one after an hour and a half.

[Rainbowheart]

Was the boy a teenager or a younger child?