I was your friend last yr., except I took my meds as prescribed ( not because I was any better, but because I was terrified of becoming my mum. )
I was prescribed Methadone, norcos & klonopin for over 10yrs. Taking opiates & benzos together is a deadly combination. I had to sign an agreement that no one would sue, if I were to die! And there's a person here who lost her mother to this combination ( & her sister, I think. )
I'm sure there must be people who have wanted to quit prescription drugs, but I wasn't 1 of em! I think a lot of drug addicts that get their prescriptions from doctors don't think they have a problem because they are "prescribed" & legal.
It wasn't until after I lost my doctor, was cut off cold turkey & I turned to H to find relief from the withdrawals, that I admitted to myself that I had a problem ( I'm sorry, I know that's not what you wanted to hear. )
If you can figure out a way to wake her up ( intervention, maybe? But, I have no idea if these work ) make sure sure it is supervised by a doctor ( or rehab ) as a person can die from these withdrawals too.
And I hate to be the bearer of more bad news, but withdrawals from benzos last a very long time. Mine were 5mos long ( but I was unable to taper. )
Since you plan on being by her side indefinitely, you need to learn some coping skills, like they teach at al-anon.
Best wishes!