I think for some people, it can be a real salvation, but at the same time, there are cases when rehabs don't help at all.

I can say that in most cases, when a person is determined, the recovery process won't go hard. You can check out Abbeycare's overview on what alcohol rehab actually is, I'll leave a link for you, and I'm sure that it won't take you long to get better. And it's great you decided to get rid of that addiction and get better, so good luck!