I mean Naruto didn't he have the powers to keep someone from dying? Naruto was able to stop Gai from dying thanks to the eight gate and Naruto was able to bring back Obito conscious or alive with his power, after Obito lost the 9 Bijuu, Gedo Mazo and did Rinne Tensei. There was no reason why Naruto couldn't do the same to Madara.
Naruto could of sealed the Gedo Mazo to Madara while keeping Black Zetsu sealed, so there no chance of Kaguya returning.
Naruto could of sealed the Gedo Mazo to Madara while keeping Black Zetsu sealed, so there no chance of Kaguya returning.