A Man Among Ghosts by Steven Hopstaken

You'll love this if you like the movie Jacob's Ladder, Stephen King's The Dead Zone or Shirley Jackson's The Haunting of Hill House. After surviving a near-death experience, David finds himself haunted by ghosts in the old Victorian house he is renovating. These tortured souls beg for his help and offer him protection from a demonic presence that wants David dead for a crime he doesn't remember committing. Even more surprising, he soon learns these are spirits of people who are not yet dead. Is this real, is he hallucinating, or is someone trying to drive him insane? As his paranoia ramps up, he discovers the truth is even more bizarre. The haunting won't stop until he kills a man named Fitz.