WHAT TO DO WHEN WHEN YOUR FRIEND IS IN DESTRUCTIVE RELATIONSHIP?

A friend of mine is in a relationship with a codependent, addictive (pot and alcohol), narcissistic, ? emotionally abusive partner not seen but others have. She is always on edge, has to drive this nob around everywhere because he's always drunk, she cries easily, become over involved in others personal struggles and grief and is fairly chaotic in her own behaviour. I find it difficult being around the nob and really have no time for him (although trying to balance being sensitive and respectful of her choice of nob). She seem rather gullible and appears to be manipulated by all his lies. One of the lies is that he's gone to the doctor about his alcoholism with liver disease and the doctor told him he will be ok, he has good genes and just needs to drink light beer. Do not believe any doctor would say that? I try to reality base my friend but she very resistant and see the good in this guy and others. When bringing up concerns with her she does want to discuss it saying I am making negative comments. But it hard to work out how to talk with her because she's very pollyanna . Basically i just concerned she will get sick again, as she's just got over cancer. A friend of hers and mine said to me once she will never leave him only unless he dies. Sometimes i feel like i'm watching her self destruct it's awful to see.