So you think Richard Wurmbrand (for example) is hell-bound? Seriously? Have you ever read any of his books? Books such as Tortured for Christ, or If That Were Christ, Would You Give Him Your Blanket? I defy you to read either book, but especially the latter, and not be moved to tears. If you are able to do that, then you had better check your radial artery for a pulse.
If he is lost coz he stupidly dared to put a date on the second advent (= false prophet), then I must wonder if it's possible for anybody to be saved.