To be fair, seeing one's soul is a lot more nebulous than he's describing. He would see the Green Knight. Her revival and his control over here would be present. But its not as if he's going to get specific memories or the like. Just the state of her soul and experiences that would heavily impact her. Like her sickness, her death.

But its like he said. He needs a reference to truly understand what he's seeing.

"All right. Then when you think you can successfully meditate for an hour," he said, and tightened his hold on her, pulling her close again.