"battled PTSD" - is there a more visual way to describe what happened? To me, battling PTSD happens largely inside someone's head. I could be wrong having very little experience of PTSD.
The true story of Vasili Arkihipov, who, when his captain is given the order to fire a nuclear torpedo during the Cuban Missile Crisis, risks execution for insubordination by trying to prevent the destruction of the civilised world.
I have no idea whether he risked execution so amend as necessary. I don't think you need a lot of the details of the story to still get the bulk of the story across - his name suggests that he's Russian. I'm not sure you even need to state he survived the K-19 nuclear disaster... although I could very (very) easily be swayed on this. To me the most important components to get across are the fact that it's a true story and that one man single handedly prevented nuclear war.
I'm going to find the book on amazon now as it sounds great!