Since you asked for advice I will break one of my rules and give some.
He had to go to detox because he is addicted to alcohol. He is now drinking again.
RUN AWAY.
I was married to and lived with an alcoholic for 36 years. The 1st 15 to 20 were OK but then it went down hill fast and I found myself living in hell. Detoxes, rehabs, hospital emergency room visits, anger, tears and a life where I thought I had no choices and only death would end my suffering. I finally woke up, realized I had choices and left her about 9 months ago.
I would not wish what I went through on anyone. You have the opportunity to get out before it gets like that.
Your friend,