Munch says so
She won't get better if she doesn't want to. If she does and genuinely works the program she'll get clean. I've seen people who went to rehab 12 + times before they were ready to work the program instead of go through the motions.

I do question the possibility of terminal addiction, someone who is totally unable to break the cycle no matter how much they want to, someone who just can't stop using. but the people i've questioned it in have been using for as long as she's been alive. and idk if it's true anyway.

so idk if she will ever get better because idk if she'll do the work and make healthy choices in her relationships. but it's not necessarily impossible. but she also needs some fantastic mental health people involved because her family life is toxic.