Keep focusing on you, and protect and care for your grandson. Maybe this will be the bottom your son needs, he'll only change if he wants to. I thank God every day for watching over me for 27 years, for 25 of those I drank and drove daily. Why I never killed anyone, had accidents, or received a DUI is beyond me, I can only assume God had other plans for me.
Good to see another resident of Scottsdale posting. If you're not already going to Al-Anon meetings you might consider attending some here
http://www.northscottsdalefellowshipclub.com/