Another tip and the most important that the majority would rather not hear about. Cancers are caused by emotional issues, traumas and hard long term feelings that have gone unresolved.
Breast cancer is about nurture or family worries and traumas. What was happening prior to the diagnosis?
There is not a histologist on the planet that has ever observed Breast Cancer cells in the blood and settle in the lungs and suddenly become lung cancer cells.
Lung cancer has several causes, it depends on the type. If she has multiple tumors through out the lungs, I'll bet it is caused by the shock of diagnosis.
If she has a singular tumor, likely she has a death wish, she wants to get out of a situation or life. These issues have gone subconscious she may not know or recall any event, but with proper questioning it can be brought back to consciousness and resolved.
Once the emotional issues are resolved then the body heals naturally without chem or meds.
As far as the emphasis on diet, a good high protein diet rich in minerals and vitamins will aid the body through the healing process.