Frank was different because he opposed them every step of the way. He seemed to be more aware than Alice that the torture happened a long time ago. That he and his wife were safe. But something kept him from "waking'. His precious Alice, his beloved baby, he had to keep them safe. He could suffer any torture, even if it destroyed his body, but he could not allow his mind to be broken. If that happened, his family would be in danger, probably even killed. His mother was a formidable witch, one not to be trifled with, but his little boy ... he was just so small, only at the beginning of his life. His boy still had a lot to learn before he could stand on his own. James and Lily ... and the little Harry ... that could not happen to his beloved Alice and Neville. It just couldn't. Better to give up on life and take the secret of his family to the grave.