He didn't like inflicting pain on others, even if it was indirectly his own. Worry lines start around his eyes at her tears and he wordlessly pulls a handkerchief out of his pocket to hand to her. Ironically embroidered with an X, probably a gift from an aunt some Christmas forever ago. He presses this into her hand, giving it a squeeze as he does. Now you know.
"She could have done so much for good..." he shakes his head. "Sometimes I do not understand what drives people to make the wrong choices." And Charles could understand more than most.
Even after all of that, he wanted to help the woman who tortured him. Because he believed she could still be saved. Very likely the same hope he held out for Magneto, though he may not voice that to anyone. Stryker, however, Charles held out no hope or compassion for him.