Yes, absolutely enough to cause serious health problems. Don't know his age, but im going to assume mid-30's. He is a straight up alcoholic. Drinking a half 5th every day during the week is really bad, and then drinking almost an entire bottle Friday and Saturday night is even worse. That kind of habit can take a person down (like death) in less than 10 years. If he has been drinking heavily his entire life, even less.

You are going to have to confront him, regardless of what you think he will do. Just so he knows what is at stake, and that you are there for him. After that, you cant really do anything to help him if he doesn't want help. Unless you wack him over the head and tie him up and take him to a detox facility (I don't recommend this, just illustrating a point). Alcohol is one of the hardest drugs to quit. Mostly because of the routine. But it is possible. He is going to have to want it though. Doesn't sound like he is there yet, but maybe he is. Won't know until you talk with him. Just be straight up with him, and tell him you love him and are worried.