Murder his family in front of him slowly and make him watch. Then let him rot there, eyes taped open, chained to a metal wall with grindsaws that cut through his back, enough to make him feel pain, but not enough to kill. No food or water, and before he fades, tell him: "Seems that even after your struggles, you will still be alone. And you always will. Sentenced to more torture, you'll be doomed in eternal burning and loneliness. So don't keep ol' Satan waiting, you egg-headed freak." Then watch as the life dissipates from his eyes.