Welcome,
He is not your son, he is an adult, responsible for his own behavior. If he choses to drink, that is up to him.
What you decide is another story, what are your bounderies with him? Have you been to Alanon meetings, or, read Codependent No More? If not, I would suggest both.
Missing work for him, attempting to keep him from drinking is codependent behavior. You could sit home for a year and that is not going to stop him from drinking, it just doesn't work that way.
Take the time to read all the stickies at the top of this forum and those at the Family & Friends of Substance Abusers, addiction is addiction, there is no difference what the drug of choice is.
Keep posting, we are here for you.