Dear OP,
You are taking an awful lot of responsibility for this: “I’ll have to look at that”, “I’ll suggest that to him”. You shouldn’t be taking responsibility for finding the solution to his problem with alcohol, he should.
What @BritInAus said above is worth repeating:
*Someone very wise said to me, you can choose to stay, but you need to accept you are staying with an alcoholic. And they will always be an alcoholic. Dry or drinking, they're still an alcoholic.
Please get some help from an organisation that supports families of alcoholics. And it's quoted a lot, but you need to remember the 3Cs. You didn't cause this. You can't cure it. And you can't control it.
All you're in control of is you. You can't make him realise he has a problem, you can't make him admit anything, or seek help, and keep seeking him... the only thing you can choose to do is the actions you take.*
I would focus on getting support for you and your children from organisations such as AlAnon. They can support you while you decide what is the best course of action for you and your children. Your husband is responsible for himself, his actions and the effect those actions have on others.
One other thing to reflect on, why did your eldest leave home at the first chance they got? Do you want that to happen with your other two?