We should be able to redo if a teammate permanently leaves at any point in the game.
We should be able to redo a game and ANY point if someone afks. The fact that someone afks and gives the enemy team a free win shouldn't cause problems for the people who didn't do anything. Give us redo's for afks so we can stop losing LP for reasons that are not our fault. Also the person who went AFK would get a full game loss and lose the LP to avoid abuse.