If he killed someone he'd be facing something else - like vehicular manslaughter.
For me it boils down to this:
In a small town with a volunteer force everyone is on call all the time. This is not the case in Wilmington - but if something big happened we might have to call in off duty responders.
So - do these guys ever get a chance to let their hair down? If he was NOT CAUGHT should he still be terminated just for drinking?
First offense? That would play into this - I don't know what his history is.
Prescription medicine? Again, if he's got a problem that he's being treated for the physician should have given him instructions not to drive.

Look, I don't care if he's seen it all and should know better. He's human and has spent his life protecting us.
No history of priors?
I say give him a break - let him keep his job.

Vog