It depends on what way the author goes with Touya. It's possible that he'll never go past demigod and will just live a normal lifespan, die, and that's the end of it. It's possible that the same happens, but he becomes a god upon his semi-mortal body dying. It's possible either of those are the case, but that his lifespan, while not unlimited, is extended. Or it's possible that they have him evolve from demigod to god directly without needing another reincarnation, giving him an unlimited lifespan.