Blue, I am so sorry you are dealing with all this. Maybe this isn't a good comment but if you can think about it this way maybe it will help. While it is terrible that your daughter was arrested, now you know about her addiction and are helping her. She could have gone along for years and gotten in a really bad place where you could not get her the help she needs, or she refused to get help.
My son also got a dui last year, a month after he turned 21. I was so upset and angry. He has paid a terrible price ( that he deserved). Thankfully, he did not hurt anyone. I believe he will never drink and drive again, and it is a lesson he has shared with his brothers and friends so some good did come of it.
Blue, I am praying for you, your daughter and sons. (((hugs)))