My dad was an alcoholic since I was a kid, I’m now in my late 20’s. It’s all I’ve ever known and grown up with. He would never change, you just can’t help some people who doesn’t wish to be helped. Although, I am not saying this is the case here but there is great difficulty when accepting and doing what’s right for yourself and your family. But I believe if it is early days, early intervention would be a huge help. There are special alcohol clinics available (free on the NHS, or if you go private, the waiting time can be reduced) and even counselling for yourself should be suggested also. It is clearly causing you pain, addiction takes a toll on the whole family, not just the drinker.
Al-anon ( https://www.al-anonuk.org.uk/) is a great charity and can provide a helpline, especially during covid-19.