At this point, Roy's return to the mortal coil is a huge, dramatic plot point, having been drawn out so long. Thus, at this point, I rather suspect it'll happen at the very end of Book 4, along with the reunion of the rest of the Order.
Which I can live with. A volume of "Oh shit, we are screwed" before the triumphant return sounds about right, for dramatic purposes. I'm sure Elan would agree with me, were he not a fictional character.