I have stage 4 endo, confirmed by Lap. I refused Lupron and used continuous BCPs to treat it for 18 months. I was only 26, so I was young enough to handle that much BCPs. I disagree with the pp who said BCPs are not a treatment, if you are on the right one, they can work very well by controlling your hormones and not allowing any new implants. And they are not as aggressive as Lupron. I went off BCPs and got pregnant within 2 months. I was told I would have many issues with TTC, but didn't, by the grace of a higher power. I have been either pregnant, nursing, or had a Mirena IUD for the last 4 years, and my symptoms have been minimal.
If your friend has not been diagnosed surgically, I would encourage her to find a good surgeon to diagnose and remove the implants and adhesions. A good acupuncturist and a diet that inhibits inflammation like a pp mentioned are also good ideas, and can help with TTC.
There is a listserve called Witsendo that was a wonderful support group for me during that dark period of my life.
My heart aches for her, this is a hard road to travel.