I think he is still alive, not realy well ( because he lost a lot of engery in AOD ) but alive.
Remember that he had special gifts to see trough closed doors and spaces.
Who said he didn't see what was coming.....
His gift warned him before the blast and took off to save his litle sorry ass and left his weapon behind which lara found.
He already knew that there was another sleeper ready to be woken up again.
His weapon didn't suposed to work by lara ( hand print or what ever / DNA ) so someone had to activate it to open the big door at the end of the level.
Only one person could do that. That person is Kurtis.