NaturalNews.com has a review this week on 2 superfood blends, including the Garden of Life product: http://www.naturalnews.com/029497_Raw_Meal_Garden_of_Life.html
I do not have personal experience with this product, but it looks very nutrition, though it's mainly sprouted grains. I don't think it's an overload of protein, but your client may also want to find a way to increase greens even more--leafies, sea veggies, spirulina/chlorella--which are not the main focus of this product.
Maybe a combination of the two mentioned in the review would be good. I can also highly recommend Vital Scoop. It's protein is clean and undenatured, it's got the good greens, and it contains flax seed.
I had a 43 y.o. client (now 47) with a more virulent form of breast cancer. She had surgery but refused all other treatments and chose alternative therapies instead, including nutrition, obviously. She juiced vegetables, ate protein that was low on the food chain, ate only clean foods and supplemented with both Vital Scoop and a greens powder blend. It's been 4 years and she's been doing very well.
RE: Her low body temp and acidic pH. How's her adrenal and thyroid function? Also, any idea about her iodine intake? Adequate iodine is closely associated with breast health and is negatively impacted by chlorine (drinking and bathing water), bromides (commercial breads and fumigated produce) and fluoride. Doctor's Data offers an iodine-loading test, which is a good way to assess its status.