It's not likely that he'll magically return since his body was burned, but sadly, Deckard Cain died in the first of four acts in Diablo 3. Cain was the lone character, besides Diablo, to be in all three games. He'd survived horrifying demon onslaughts, being locked up and left for dead in Tristram as it was burning to the ground, as well as being hit by a 'falling star'. Despite all of that, he died kind of pathetically and undramatically as players sat and watched, unable to save him.
R.I.P. Deckard Cain. You won't be forgotten.
"Stay awhile and listen."