Oh dear! My heart sinks for you when I read this last post.
You’re right, he’s not a heavy drinker, he’s an alcoholic. And you have spent your time caring for his children and trying to manage his drinking. Which , as you know, doesn’t work. However hard you try. You didn’t cause it and you can’t cure it.
So you have two children to support, probably single handed. One has complex needs. You need advice now on what benefits you are entitled to, so that you can pay the rent alone.
I’m afraid it’s unlikely that he will pay child support for his children , but of course you must try to agree this.
I think it’s also likely that you will have 100% care of your children . Please remember that contact with the children is for THEM and not for their father. It’s about their needs, not his.
I know it’s hard to think like this because, as a PP said, when you live with an alcoholic everything is about them. He has trained you well to always think of him first ( and last ) and never talk about it with anyone, thus making sure that he has all the support and you have none.
I understand you must feel so betrayed when you hear him talking to his mum about you like that. When you feel you have done everything you can to help him. For addicts, nothing that you do for them is enough. They are bottomless pits of need.
Do you have any ( external ) support with your oldest son? Again check what you can get as a single parent. You will undoubtedly have to make a huge fuss to get anything I’m afraid.
What about your family and friends ? I’m sorry to hear that you have lost your own mum.
Have you been in touch with al-anon ? I know it might be hard to get along to a meeting but please try to do so. My sister was in your situation and al - anon saved her sanity and probably her life.
You can’t fix your partner. But you can take all that energy and resourcefulness that you have spent on him and start spending it on YOU and your children.