Dawson's Dad (SPOILERS)

I guess it doesn't matter too much at that point; Dawson is dead and won't return no matter what happens to the dad.

The dad is a loser with no future whether he rots in prison or overdoses or gets killed in a drug conflict.

Agreed. We've seen him beat his son, beat an old man, destroy the old man's last tangible connection to his late wife, kill a expected father, attempt to bring the long dead father's son into his criminal lifestyle, and finally kill his own son and nothing. The guy was a real POS and by this point, I would've accepted a Lovely Bones style ending where he turns to get back into his truck to flee and accidentally drops the gun causing it to go off and end with a head shot.

I am pretty sure that off camera the police probably figured out that Tommy Cole was angry at being arrested years before and went after his returned son for revenge because of his time in prison, never mind that Tommy didnt feel any remorse at beating up Tuck, causing the death of the kid years earlier or treating his son and family like crap without any love and deserved to be arrested and go to prison in the first place.

If the police did not arrest him they would be idiots, the death was an obvious homicide, an the guy was stupid and would probably eventually either OD or his own drugs and alcohol or end up messing with another scumbag and get killed or shot or beaten because of it by them, he had little or no future and was already less than half the man that he was when we see him as an old man anyway.