Nah, pretty sure he would have mentioned that

To be fair to the person who you replied to - I didn’t know that Vonnegut was a POW in Dresden and survived the firebombing until after I had finished the novel. While reading it I just attributed it to his fantastic imagination and assumed it was all metaphor. Then I learned how much of it was not, in fact, metaphor.

His sister also died of cancer two days after her husband died in a freak train accident. My memory was they didn't tell his sister that her husband had just died. My memory is also he took in her children after they lost both parents within a two day span. Dude had a lot of trauma in his life.