I liked his idea and used it.
This specific island is a part of the Goddess of Life's Realm. Animals are big because of this. Everybody recovers HP twice as fast and healing spells have their power doubled. Because of that, I said that his body is unable to die, but his soul departed it. As it's a PbF, I can run two settings at the same time.
Thus, the party was supposed already to get some water from the deepest fountain in the island, to save a girl from a curse and bring her back to life.
Now, the party has to get two vials of that water, one for the girl, one for the rogue. But it can be fruitless if only they succeed.
Because at the same time, the rogue is lost in one of the other gods' realm, and he has to find his way out.
If they can get the water and he can find his way out, then he'll be back to life. If only one of these things happens, then he's dead forever, and will have to create another character, one level lower than his old one was.