Discovery will not pay for Chemo therapy

I write in behalf of a female friend, Santhoshika, who was a leukaemia recovery case as a child. As an adult she developed other cancer, was treated and has been in remission for about a year or two. Previously she was insured by Sanlam when she had the chemo therapy. Lately she changed to Discovery. The cancer has reappeared and Discovery has refused her chemo therapy. WITHOUT KNOWING THE DETAILS of her case history, but reacting to that which I know, I must state that with this uncompassionate attitude, Discovery is effectively sentencing her to death......Please help!!