I really feel for your daughter, when someone tells you there is basically nothing they can do, why would you feel the need to ask any further questions?
I can't remember what stage my endo was at, I believe it started when I was about 14 as my periods were horrifically painful. I was told by unhelpful male GP that I had to accept my painful periods as I was female. Given painkillers after a few years of going back to GP.
Eventually, I saw a female GP when I had almost collapsed from the pain, she said endo, saw gynae who also said endo.
I read everything I could on endo and overhauled my diet to help me.
Did round of drugs starting with Dydrogesterone (Duphaston) as I had already been on the combined pill previously. When that didn't seem to help I went onto Buserelin, like Zoladex it puts the body into a fake menopause. I took HRT tablets too. I was 27 at the time. Although it helped my endo was aggressive and it continued to get worse.
Booked for laser lap and dye. Was told after op that they weren't even sure if my left ovary was producing eggs, my scar tissue was mainly in my pouch of douglas (explained why smear tests were tear inducing) and I had severe scarring on the ligaments in my pelvis.
Because of my age (28) and the fact that I was married etc he advised me that if I wanted a baby then to start trying as I would probably need clomid if not IVF. We were devastated. The only other option open to me was Danazol which I refused.
I was pregnant in 2 weeks!!!!
I don't know who was more shocked me and DH or the gynae 
We think it happened as my body was an endo free as it could be. I went on to have another baby 3 years later.
My lifestyle is very relaxed, I have little stress and I think this helps me massively re endo. At present I am not on any meds for it and only have pain when I ovulate and when I am on my period.
Your daughter needs to be referred to another gynae. You can hire TENS machines from lots of places and she can try one before you purchase one.