I am so sorry that your son is so deep into alcoholism. I am so sorry for the pain that causes you. This forum is a caring, compassionate place to come, full of people who really understand what are you are going through.
Come often, tell us how you feel, what is happening, and know that you will be heard and cared for.
This is a time to take care of you. As difficult and incomprehensible it is at some level, you cannot make your son's decision for him. Remember the three c's: we didn't cause it, we can't control it, and we can't cure it.
All you can do is focus on your own life, your own recovery, as bitter a pill as that may be to swallow.
Let me ask you this: If you changed your name from "Leftover" to something that speaks of your inner strength, your resilience to make something positive, something healthy, of your own life, what would your new name be?
This, I think, is the path to look at, the path to recovering from the stress and physical illness your grief is causing you. It may be that, if your son were himself and not ravaged by this dreadful disease, he would tell you not to waste your own precious life on grief for his damaging choices.
Take care, take heart despite the pain,
ShootingStar1