Ok Nicole, sounds like you didn't see signs of narcissism or sociopathy before his crisis. That pretty much leaves bipolar or drug addiction as likely explanations for his peculiar behavior in his larger life (which may or may not have anything to do with the marriage).
You mentioned road rage - this can be a depressive sign or could occur with mania. (My ex, who I believe has a mild shadow form of bipolar, became an aggressive driver during his crisis times.) Did he have any signs of depression or mild mania in years past? Is there any history in his family of suicides, psychosis, mania? (I remember my ex's sister, when she was primary caretaker of her four children under age 6, stayed up all night to paint a bathroom. In retrospect, that was SO manic!!).
And what about drugs or alcohol? What was his intake like in the past? Are you aware of any substance abuse issues? How much did he drink? He could well have PTSD from his experiences in his home country and could be self medicating.
Something just isn't adding up. The marriage is one thing - there could be lots of reasons for him to decide marriage no longer suits him. But adding on the lackadaisical attitude towards his work and patients -something is very wrong there.
