Hello Talomera,
I wish I could tell you some magic way to talk to your son so that he would see how self-destructive he is being...never found those words with my stepson. I think it's always good to keep the lines of communication open--with one caveat. If he is verbally abusive or threatening, you have every right to end the call and refuse to engage.
Watching someone we love behave without regard to their own future--even their own life--is gut-wrenching. I'm so sorry you are going through this. Although I've never been a reglar attendee of Al-Anon meetings (for friends and family members of alcoholics), I have been helped a great deal by their concept of the three C's.
I didn't Cause the alcoholic to drink.
I can't Control the alcoholic's behavior.
I can't Cure the alcoholic of their addiction.
It's just that simple--and just that hard especially with someone you love so much!
Hang in there!