I believe my mom has PTSD, as did her mom. It wasn't diagnosed in the general population back then, and it was called shell shock with veterans. I have never heard that most of cPTSD comes from Narcissistic parents. Are there that many people professionally diagnosed with it to come to that conclusion?
I read several books on parenting when I had my son, and it helped a great deal. I tried my best to not pass on the abuse, and I didn't.