Which sentence in this excerpt from Leo Tolstoy's The Death of Ivan Ilyich shows that Ivan Ilyich's son is still innocent and uncorrupted, despite the people around him?

His son had always seemed pathetic to him, and now it was dreadful to see the boy's frightened look of pity.

Their daughter came in in full evening dress, her fresh young flesh exposed (making a show of that very flesh which in his own case caused so much suffering), strong, healthy, evidently in love, and impatient with illness, suffering, and death, because they interfered with her happiness.

Fedor Petrovich came in too, in evening dress, his hair curled a la Capoul, a tight stiff collar round his long sinewy neck, an enormous white shirt-front and narrow black trousers tightly stretched over his strong thighs. He had one white glove tightly drawn on, and was holding his opera hat in his hand.

Following him the schoolboy crept in unnoticed, in a new uniform, poor little fellow, and wearing gloves. Terribly dark shadows showed under his eyes, the meaning of which Ivan Ilyich knew well.

His son had always seemed pathetic to him, and now it was dreadful to see the boy's frightened look of pity. It seemed to Ivan Ilyich that Vasya was the only one besides Gerasim who understood and pitied him.

They all sat down and again asked how he was. A silence followed. Lisa asked her mother about the opera glasses, and there was an altercation between mother and daughter as to who had taken them and where they had been put. This occasioned some unpleasantness.

Fedor Petrovich inquired of Ivan Ilyich whether he had ever seen Sarah Bernhardt. Ivan Ilyich did not at first catch the question, but then replied: "No, have you seen her before?"

"Yes, in Adrienne Lecouvreur."