When that knock came to the door, Derek already made a face. He knew who it was. Once opened he would come to stare down at Malia for the moment. Only to listen to her plea. She wanted to see how he was with her own eyes. Didn't these kids realize the damage they did to this stupid human? Still, Derek had a bit of sympathy for Malia because of what she went through. Plus, she cried on face time with him the other night.
"He's not good." Is all he said first to her as he let her in. "He's up in my room." He came to grab Malia's hand. "You can see him, but that's it. He can not leave here Malia. He needs to heal, away from you and Scott." He made sure to tell her this as he motioned up to his bedroom.
Derek on the other hand, wasn't stupid. He made sure to have mountain ash on the window edge so no one could enter or leave. Except through the front door, and passed him.