depends on how fearful the dog is but imo no you cant fix it, you can only manage it. a dog should be your best friend that you can take everywhere and enjoy your time with. not something you need to constantly worry about. a pet should be therapeutic and not a source of stress.
you can try really hard with a dog and train constantly but sometimes its more humane to put a dog to sleep than have them sleeping with one eye open and nervous and fearful for 10+ years of their life.