You can hear what sounds like the impact right at the 13:07 mark when the pilots transmission cuts off right at the end of his callsign, 10 seconds later tower states Radar Contact Lost.
Also, additional excerpt from the updated NTSB Narrative:
"Examination of the wreckage did not reveal any preimpact failures or malfunctions. Toxicological testing of tissue specimens from the pilot detected butalbital, (a prescription barbiturate typically used for severe headaches) bupropion, a prescription antidepressant also used for smoking cessation, and ethanol. The butalbital detected was consistent with use within 24 hours before the accident, and studies have shown butalbital can impair a pilot's ability to fly; however, the actual level of butabital in the pilot's system could not be determined because of the lack of fluids. It was not possible to estimate from the toxicology when the bupropion might last have been used, but this medication has been associated with an increased seizure risk. No fluids were available for analysis, so it could not be established whether the ethanol found was from ingestion. The pilot, a physician, had a history (known to the Federal Aviation Administration) of alcohol abuse, but the pilot did not note the use of any medications or any medical conditions on his most recent Application for Airman Medical Certificate. The role of the pilot’s medications, possible medical conditions, or possible alcohol ingestion in the accident could not be determined."
Listening to the audio, it doesn't 'sound' like he's intoxicated, at least not heavily.
I used my pharmacology program from my FF/EMT job and butabitol is a pretty decent pain-killer and subject to addiction. It notes to prescribe with caution in pts. with history of alcohol or drug abuse because of it's adddictive effects. It's common side effects are intoxicated feeling, drowsiness, sedation, dizziness, among others. Definitely NOT a drug I'd be flying with in my system.
RIP, hopefully someone will learn something from his mistakes.