@naturalbaby
I'm going to have to agree with @CharlotteByrde ,who doesn't sound like a hard hearted bitch, but a 'truth teller'.
One of the first things you learn at AlAnon is the three Cs;
"I didn't cause it"
"I can't control it"
"I can't cure it"
A fourth C is often added:
"I can take care of myself"
You cannot help him. And by taking him in you are actually enabling him.
My 'first alcoholic' was my brother. I was an enabler, a 'rescuer'. It was only after I stopped rescuing him and told him "I will not have anything to do with you when you are drinking. Do not call me, do not come to my house" did he finally get sober. It wasn't immediately, it took some tries and some relapses but he's now been sober 11 years and living a wonderful life. Right now he's in South America visiting some old friends and sending me wonderful pictures. He and I are planning a trip to the UK in a few years. We are both 'free'; him from alcohol and me from being an enabler.
My 'second' is my estranged DH, married 38 years. His drinking spun out of control 19 mos ago. I tried to curb his drinking, I failed. I tried to 'carve out my own life' whilst living with him in our marital home, I failed. I left 15 months ago after his verbal and emotional abuse escalated to the point where I was escorted out by the police as he would not let me leave. I've obtained a legal separation and he's still drinking and in our house. Our marital home is a disgusting mess and he is falling apart, physically and mentally. But he is doing this to himself and there is nothing I can do to stop him.
Don't do what I did, try and try and end up with a broken heart. I know you love him. But love is not enough. You can love someone to distraction but that does not mean they are right or healthy for you. Trust me, I know. I will love my esDH until the day one of us dies, but I will never live with him again. There has just been too much pain, and too much lying. My trust is broken, along with my heart.
Let him go. I know it feels like it will (figuratively) 'kill you' to walk away, but in order for you and your teen DC to thrive and for him to hit rock bottom and get the help he needs, you simply must. Tell him you are through and he needs to get help. Tell him not to contact you and that if he shows up at your home you will not let him in. And follow through.
AlAnon was a perfect fit for me. I'm in the US and they have both in person and online meetings, I'm sure it's similar in the UK. There is also an organization called SMART friends and family, they are mostly online. Make it a priority, I'm sure your teens will understand if you need an hour or so online for a meeting.
You can do this. Yes, you will wobble and wonder if you did the right thing, but in the end you'll know it was the right thing.