In the movie, though Poppa gets swept away very early, you don't see a body. The film shows an image of his grave -- and you just assume the worst. However, Raymond Ochoa, the voice of "Good Dinosaur" protagonist, Arlo, tells The Huffington Post things may not be as they seem.
When we asked Ochoa if he thought Poppa was actually dead, the actor said, "I don't think so. They always leave it open. In some movies, such as 'The Lion King,' you see Mufasa die, but in this movie you really don't. He’s swept away, so there’s always the opening to bringing Poppa back."