I think you should read the NTSB report more carefully.
Although witnesses reported the pilot removing alcohol from the baggage compartment (which isn't accessible during flight) and a bottle of wine from the cabin, none reported any smell of alcohol on the pilot. However, witnesses did report a smell of alcohol in the cabin.
Subsequent examination of the plane found that the pressurization system had a problem that would have probably prevented it from maintaining the appropriate cabin altitude. Combined with the pilot's heavy smoking habit (3 packs/day), the most likely cause of the pilot's disorientation was hypoxia.
He was at 13,000 ft when he had his “problem”. Hardly hypoxia country. Millions of people live that high. He left the scene after cleaning up the aircraft and wasn’t tested for substances. He asked the witnesses to lie. He didn’t know what state he was in for crying out loud? The symptoms of hypoxia go away almost immediatley when ox is reintroduced. I’ve been through altitude chambers. Trust me.