i cant give advise on what to say to him. ya got good advise already. what i hope you can understand is that he isnt a bad man, he is a sick man. if he is an alcoholic like me, he does care and knows what it would mean and its killing him deep inside to know alcohol is in the drivers seat and everything/ everyone else is in the back. i missed out on many, many occasions of my sons life because i chose alcohol and it was killing me inside, but i couldnt stop.
i am truly sorry you have to go through this and hope and pray you will have a great graduation.