Sorry you’re struggling, we have been through & are still going through this for BIL.
The short answer re rehab basically is- no. The NHS can technically fund it, but very very rarely do. You have to exhaust every other avenue first- GP, talking therapy, community services so group therapy, you get a key worker allocated, lots of meetings and talking but very little actual help.
When that inevitably does nothing you progress to medical detox, depending on usage and how willing they are there’s a few methods here. You can do it at home with support which is basically reducing intake by 10% every other week yourself, didn’t work for BIL who just snuck out to drink more. Second option was to go to the clinic once a day for medication dose, again didn’t work for BIL.
The NHS don’t routinely fund residential rehab, that’s a private thing you’d have to pay for. The only way you could try to get the NHS to fund it is by trying and exhausting all other options first, then if you are high-risk, homeless, or have other health issues you can go to a panel to ask for rehab to be funded. We tried this and despite double digits of A&E visits, police bringing him home etc were knocked back. It’s such a high bar that essentially unless they have nowhere to sleep it’s a no.
Start with your GP because a lot of the help runs from there, but for speed you’d be better off privately funding any treatment you can. My husband & I paid for therapy, treatment & rehab in the end for BIL at his request but yet even now over a year later he is no better off sadly. Good luck x