“Maybe I failed this time, but… I’m not giving up. I’ll show them I’ve got what it takes to make the hero course, and I’ll become a greater hero than all of you!
| ★ Shinsou Hitoshi ★ | Happy Birthday to my lovely Aseel bby! @genosus (ノ≧∀≦)ノ♪♬

So after watching Moana for the millionth time, I realized why Gramma died when she did.
It’s because she no longer was holding the Heart of Te Fiti, which has the power to create life itself. It was keeping her alive, which is why her health declined so rapidly after giving it Moana.
And she probably knew that. She knew that she would die, but gave it to Moana anyway to save not only the island, but the world.