Did he go to OCS? It would be unusual to be commissioned an officer right after college without something like OCS UNLESS someone H E L P E D push the paperwork through. Doctor's etc, are another matter. I don't recall seeing anything like ROTC or OCS in Kerry's military info. Even OCS requires some enlisted time and a recommendation to OCS.
February 18, 1966 Kerry formally enlists in the U.S. Navy
August 22, 1966 Kerry reports for Naval Officer Candidate School at the U.S. Naval Training Center in Newport, Rhode Island