http://www.seattleweekly.com/features/0527/050706_news_andy.php
This is from a few days back, it claims he was in the hospital on 5 July. Then again, it is a Seattle-based newspaper, which tends to sacrifice facts in the name of emotion.
If reports of his demise are not exaggerated, I'm certain we'll see an obituary in Seattle's daily paper or this one in due course.
Technically, it's the Seattle Weekly, which is a tabloid, not a newspaper. If the Weekly announced that the sun would rise in the morning, I'd pack a flashlight.
Like I said, I have my suspicions, but they don't rise to the level of proof. What I'm keeping my eye out for is a memorial service. You'd think that after hundreds of strangers selflessly scraped up $50,000 in an ultimately-futile attempt to save Stephenson's life, his survivors would have some sort of public memorial to allow the anonymous benefactors to pay their final respects.