I'm so sorry, Liz. How truly awful for your son. I'm glad he wasn't seriously hurt.
I don't know that your ex is "headed for death soon"--you'd be amazed at how long some alcoholics can go on this way. My second husband is still alive after almost 20 years of continuous drinking--AFTER nearly dying from alcohol-related causes.
I hope your son has decided that he will not spend time in his dad's company if he's been drinking. He could, of course, file a criminal complaint for this incident. Even if a person is in a "blackout" that does not relieve him/her of criminal responsibility for their actions under the influence. I'm pretty sure he won't go that route, but it might be good to explain to him that the law wouldn't excuse his conduct. And he CAN call the police if he ever feels threatened.
Hugs,