twohourssleepandamigraine I am so sorry for your daughter being put in this horrible position.
Please listen to your daughter who does not want a relationship with this man.
"I am just so upset that he got a wake up call and didn't heed it."
It is not your responsibility to make him heed the warning, nor is it your daughter's.
"I genuinely don't understand parents who refuse to put their children first, but I don't want her to grow up without her dad."
He cannot put her needs first, because he is addicted. However, you can put her needs first but you seem to be hesitating because you are hanging on to a fantasy that it is better to have a shit dad than no dad. And that is not true.
"When he's sober, he is an OK person" Not much of an advert for a father for your little girl is it, a man who is only OK when sober and struggles to be sober. Maybe he will get sober, maybe this will make him come round.
"I guess I'm in denial about his denial and have to let go of the person he was. He isn't that person, or daddy, any more." I feel you are making this a bit about you, your expectations of him as a parent. BUT it is not about you or him, and I am sure you know it, it is about your dd.
You are enough for her.
Ensure he only has sober, supervised contact if she wants it and do not allow him to put her in this position again, please.