There’s the truth he knows, and then there’s the truth beneath the truth he doesn’t reveal. So when a young man comes to him enquiring about the king’s future, he already knows the answer.
He knows the young man knows the same answer, because the future isn’t so hard to predict when it’s one’s own, and when one has clearly made a definite plan to execute.
The young man is a schemer, and so when he gives him his answer, his mouth tells him it’s okay to lie, but he tries to use his eyes to say what he can’t; to tell the young man the truth behind the truth.
It’s a gaze that a softer man would understand, but it merely makes this man embarrassed at the pointed attention. So he ends up crying, and thinking that knowing too much truth will turn him into someone he never was.