https://en.wikipedia.org/wiki/Alcoholic_hallucinosis
My sister has had a problem with alcoholism for some time. She got a DWI over a year ago. She lost her job after playing the points + FMLA game too much (because of her drinking).
It’s gotten to the point where she constantly has the shakes and is now experiencing audio hallucinations. Maybe visual that she’s not communicating well, but definately audio. She hears music from a disconnected radio in a room. She thinks it’s supernatural in origin.
I even went over with all kinds of high tech recording, ghost hunting equipment, sensors everything. It was all negative for that stuff. I did multiple experiements trying to prove to her this including her recording what she thought she heard and me recording at the same time. Both recordings were just background static. Except she swears she hears it on hers. I understand she thinks it’s real, but it’s absolutely advanced withdrawl. She is in denial. She’s been trying to be clean but in denial of the symptoms and how dangerous her current conditions are.
Does anyone have experience themselves or friends / family dealing with this? How to approach or convince them to seek treatment before it kills her. Anything to give them outside of a hospital ride?
Edit -
Thank you for all the kind responses. 
Edit 2 -
I went to go check on her, give her a care package and maybe try to convince her to go to the hospital. The first thing before I said anything was “I think you’re right. I’m hallucinating. I’m sorry.”
Her tremors were down but still there. She said she was starting to visibly hallucinate and trying to understand what the triggers were. She declined to go to the hospital still, but it’s a step in the right direction with her able to start thinking critically about it and acknowledging her condition.
Thank you all again. 
My dad supposedly hasn’t had symptoms of psychosis, but he very recently decided to dry out on his own without medical treatment, and it was bad. He came out of it fine (supposedly) and I can share with you what happened but it’s pretty scary and I don’t wanna freak you out.
If she is quitting alcohol, besides inpatient detox there may be places near you that do outpatient treatment with medications and trained staff, possibly with peer support options.
Ideal Option has clinics in multiple states and are an agency that provides this kind of care, if she would be more open to outpatient support.
Also, to address the psychosis in the moment: sometimes telling someone that what they are experiencing is imaginary can do more harm than good, especially depending on how severe the psychosis is. It sounds to me like you did an awesome job of reality testing with her to try and get her to maybe believe that there is something else going on. At this point, I would personally tell her that even if no one else experiences it, it must be frustrating/scary/etc. and validate her feelings. Because it IS real for her right now and probably really distressing. That might be able to break through some of her resistance if she just feels like she’s being listened to. Sometimes I’ll ask questions, like when did you start hearing this? How does it make you feel? Why do you think you can hear it if no one else can hear it?" And maybe make ypur concerns a bit more about you. “I care about you and I’m worried, if anything for my sake can we just go talk to a doctor or just try this thing that might help? And if it doesn’t, we can try something else”. Could be good for her to hear about how it works from a clinical standpoint too depending on what kind of person the is/how cogent she is at the moment