Like many previous posters, I have done much the same concerning PC death during an adventure. If the party is too far away from civilization, the player can take over an NPC for the evening. If there are no NPCs, I have the player help play the monsters. Sometimes, if the player has a backup character ready, I have used the prisoner routine as well. Recently, the party was deep in the mountains, One of the PCs died fighting 2 trolls. I had several thiings planned for this PC so I arranged Divine Intervention. A bolt of lightning came down from above and struck his body. One of the PC clerics went over and noticed he wasn't quite dead yet. Of course, the intervention wasn't from his god so there will be dues to pay and such.
As a player, I've had my character die halfway through a session before. I usually end up playing an NPC for the rest of the time or finish tweaking one of my backup characters.