Draco didn’t know why he would ask that. What did Snape mean? And then he realized that there was Snape’s portrait at Grimmauld Place. That meant he knew what happened in the past few months. Snape was too sharp to not notice. Draco wondered if he should deny. He had been denying for so long. But Snape had been forthright with him. So he responded honestly, "I am scared.’