Honestly at that point I'd just leave the reaper dead lmao
Being new and learning is one thing, but after a certain point the dude who's dying to every other mechanic stops being worth the resources to raise. If the group can clear without them they can take the time on the ground to watch and learn the fight, cause if it's that bad it'll probably be faster to just 3 man it than to keep throwing bodies at the boss and possibly (probably) wipe again.