i think we've established that the police fucked up by not alcohol testing him, given his history.
WTF? This has NOTHING to do with you pretending to know everything about this man, about his life details, his thoughts, his wants, how he percieves himself and exactly what went down that night.
But, lets entertain your dumbass idea for a second.
If they suspected he was drunk, they wouldve tested him. You dont think the PD is that fucking dumb do you, that they wouldnt be able to tell if he smelled/acted buzzed? I dont know about you, but I can tell instantly if someone has had anything to drink.