Stunt, this is my bread and butter, so I am happy to communicate via Messenger if you want.
The recommended limits are 14 units per week for a female, and 21 for a male. Most folk will consume most units at the weekend, so I would be concerned that he is drinking that much during the week, especially as he works, and no doubt drives to work.
You have done right to say you are concerned, but nobody stops drinking for others, even spouses or children. They have to stop drinking for themselves, and will only stop drinking when they begin to see it as a problem. In my line of work we tend to double reported drinking amounts, but as you are there, and seeing the empties, you will be able to get a more reliable picture of the situation.
I would encourage him to keep a drinking diary, time, amount drunk, who with, mood etc. When is his first drink of the day?
Can he go a day without alcohol, or longer?
Perhaps a check on his liver function might help. If levels are raised, that can scare some folk into changing their habits. The liver can recover very quickly until it reaches a certain point.
What are his thoughts on his drinking? Why is he drinking? The diary would cast some light on this.
If he wants to reduce his drinking he could go to his GP who would refer him to the local alcohol team, or he may be able to self refer. It depends on area. This will only work if it is him wanting help.
Whether he wants help or not, I would encourage you to look into local family support. There is usually something around, and talking to others who have similar experiences will be very helpful.
How is he when he drinks? If there is violence, or you feel scared or threatened, then you need to give serious consideration to your future together. Sadly with alcohol things often get to rock bottom before people will change.
Anyway, send me a message via FB if you want to chat further. Well done for sharing. That is the first step 