If he "needs a drink" after a rough day and that one drink turns into 5 or 6, he very well could be a binge drinker. Alcoholic? Maybe not YET. Google binge drinking and see if that describes him. Good luck :-)
Alcoholism/addiction is a dependance upon a drug (or a chemical that alters mood, thought, or action). My sister has been sober for over 9 years but she still considers herself a meth addict. It really doesn't matter how long or how much it comes down to chemistry. If you feel anxiety, stress, pain, confusion without said drug and you need said drug to feel "normal" that is an addiction.
Yes. They are called binge drinkers. But are you sure he is an alcoholic? How much does he drink?