Need advice on continual vomiting and vomiting oil.

[Muj1312]

Backstory: So my girlfriend has been brought up with little to none medical attention. Her family rather wait for something to go than to go the doctors. She got scolded for taking paracetamols during her period pains. This is why im asking you so I can get a better understanding on how serious everything is.

So my girlfriend has been coughing for months now. Slowly, her repetitive coughing (mainly in the night) has turned to vomiting. It is common for her to vomit once a night now. She also vomits if she over eats.

She described her last puking episode to be more oily. As in she could see oil in her vomit. She claims its nothing because her lasagna was oily.

She doesnt want to go to her doctor nor the hospital. I KNOW (i have no prior medical knowledge) that it is serious.
I need a diagnosis to confirm it and natural methods (for her) to stop it.
Providing life threatening data to back up your answers will be kindly appreciated.

Help me save her!
Thanks!