We officially think he's still alive, they have been looking for him in the Pakistan/Afghanhistn border area since 2001...
If we thought he was dead, WE would do the 'Ding dong the witch is dead' thing all over TV...
He's alive.
As for his kidney trouble, this guy has enough money to buy himself a dialisis machine, generator, and pay a personal surgeon to run the thing... He's probably lying in a bunker somewhere, on the box, and too weak (or possibly perminantly injured/deformed by close contact with one of our 'care packages') to appear on TV...
He has released further video in the last year, however it was not concrete, could have been pre-taped, and he did nothing to convince the world that it was not (IIRC, he made references to Iraq, but even a blind man could have seen that war coming)...