Sure, it stinks.
Now, let's see if the NTSB folks can peel it apart--especially in light of him bugging out.
Common tactics for DUI hit and runs are to leave the scene, on foot, if possible/necessary, and hide out until all the metabolites and alcohol are out of their system. It also gives an opportunity to ditch any illicit substances they might have on their person.
Lawyering up, under the circumstances, is one thing anyone would do, but implies he didn't forget he might be held civilly or criminally liable for the wreck.
Cell phone records might be worth a look, too.
"I don't remember" sure could be a convenient way to keep from providing the little details that trip up a story full of lies.
The question is one of if the interrogators are sharper than the scam, provided there is one.
In the meantime, they avoid the whole persecution thingy the rainbow flag set likes to wave around--which may or may not have any relevance to the wreck at all.
For those into computer simulators here is an AMTRAK sim.
https://www.youtube.com/watch?v=idCS9mqXtzk