No word on whether he will actually get credited for the rewrite, but he definitely did extensive work, and this was, according to Sneider, at the request of DiCaprio.
I didn’t love Killers of the Flower Moon and after hearing PTA did extensive rewrites on it, I felt like I could see the seam a bit. I think PTA is an amazing writer, but he writers for the way he shoots and directs and I don’t think it meshes with the way Scorsese works.