In JoJo's Bizarre Adventure: Golden Wind, we know that Giorno can heal people by restoring parts of bodies to people. We have seen that he can heal a body so much that Bucciarati's soul, instead of moving on to the afterlife, instead stays in his body. We saw that Giorno healed his own body and jumped right back in after Narancia's death.
Now Polnareff, when we last saw him, was in the body of Coco Jumbo. Because Polnareff's soul did not go to the afterlife, he was stuck in the turtle.
Why then didn't Giorno go to Polnareff's body and heal it, then stick Polnareff's soul back into the body?