The call on the field was not a fumble recovery. So in order to get it overturned, there would have to be definitive proof that it did NOT hit his helmet. Not the other way around. It was too close to say that IMO. However, I think the premise of the rule is pretty dumb. I don't think the ball should be considered out of bounds unless someone with possession is touching the ball. Otherwise, the ball itself should have to be out of bounds (like when a player slaps it out). It tapping someone's helmet who is sprawled out of bounds is pretty silly.