I agree with Meli...the drinking and the endometriosis are not related. The more you drink, the greater your tolerance for alcohol. So, over time, it takes more and more alcohol to get you drunk. So, she is likely drinking to get the same "buzz" she used to get, but it now requires more alcohol. You do need to get help for your friend. Often, depression is an underlying issue for those with alcohol addiction. It seems like the alcohol helps temporarily. But, in reality, it makes the depression worse and creates a vicious cycle. It is important that she breaks the alcohol addiction before other serious issues become part of her life. Take care!
It sounds like your friend is suffering from multiple problems, one of those problems being alcohol addiction. I have been around alcholics my whole life and I have had extreme problems with endometriosis, so I do have a ton of info on both problems if needed.
How long has your friend suffered from endo and did she start binge drinking after she was diagnosed? How severe is the endo and how has it affected her mentally.
I ask because even though they are two different problems and are not connected to one another, endometriosis can lead to depression which can then cause problems with addiction.
The endometriosis has nothing to do with how much alcohol she is consuming, it sounds like she is able to consume so much because her body is becoming immune and addicted to alcohol. You are correct when you say her drinking may be causing more damage, it does and it will cause more severe damage. It is a very serious problem and should be brought to attention!
The issue with her endometriosis also needs proper medical care, because it too can and will lead to more serious issue's if it is not watched. Also, women with endometriosis should not drink alcohol because it has been shown to cause more problems/severe symptoms with their endometriosis.
Honestly I know you probably do not want to cause issue's between the two of you, but I would suggest that you find a way to let her parents know about her actions. Both issue's are dangerous and can lead to more serious problems.
As I mentioned above I have a ton of info on drinking problems and I run a web sight that focus' on endometriosis, so if you need any help or more info please feel free to ask me anything. I wish you and your friend the best of luck.