So what, it didn't hit his hand? If it had then the goal would have been disallowed for handball, but it didn't and hit hit Grealish's hand.What's a natural position? The attacker heading the ball toward Grealish had his arm above his head while stretching to head the ball. Unless you are arguing it was a deliberate handball by a player with his eyes closed.
Where in law does it say that having your eyes closed means it isn't a handball? And I am absolutely not saying it was a deliberate handball, because law is very clear that if your arm is not in a justifiable position for the action being taken then it is a handball even if accidental. As I've already said, I could accept either viewpoint as to whether the arm was in a natural position or not, but saying it can't be handball because he had his eyes closed and it was accidental is just not in any way supported by law.