October Novel Prep Challenge

Yes, that might be a good start. And maybe some study on mental disorders, since he surely is affected by some sort of trauma disorder based on that history - abandoned by his father, deceased partner and newborn that he didn't even know about - he probably had some sort of survivor's guilt, too? I'm no psychologist, which is why I would personally research the possible mental health affects that could be plaguing him because of these past traumas. Then, after understanding the potential disorders and how they manifest, then I might write some short stories around your protagonist... Maybe he was triggered at some point and lashed out, got in trouble with the law or a neighbor with bigger guns. Maybe he tried to commit suicide and we met an angel in his life who talked him out of it - a friend, a neighbor, an early encounter with the spirit who shows up later in his life to guide him on this quest you're writing now. You'll probably get more ideas when your research symptoms.