Yes, and no you can hear voices and have psychosis in bipolar as I have bipolar and I have psychosis. One of the best medications is Lithium as it reduces aggression. I take it and its reduced my aggression and I no longer get rages in mania.
As for the PTSD, therapy and time are the best healers, I know therapies not for everyone, its not for me, I healed on my own, but maybe its worth a try for him. Good luck x.
People who experience PTSD often experience the world as a much more dangerous place than the rest of us. I think PTSD can explain all your fiancé's symptoms. A doctor would probably give him some anti-anxiety medication, but make sure it's not benzos, which are addictive.
Have him ask his doctor for something that's not addictive, and urge your fiancé to get therapy. My guess is that he's no so much hearing voices as experiencing significant so much anxiety that he thinks people are calling his name. Mild meds and therapy can help him in time return to a much more normal life.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.