Stephany,
Either this doctor did not graduate or someone did not hear correctly.
This cancer does in fact spread, it does in fact spread to organs, and I really think you need to get your mother to another cancer center NOW. Do not wait, call today!
PS, in a different post you asked me if I thought her draining wound was thrush, the answer is no. It sounds to me to be a fistula. Fistulas happen when bad stuff wants to get out of the body. Cancer can cause a fistula as can infections or other fluids that need a way out.
I don't like that her doctor isn't explaining things well. It may be that he is right; that her cancer is not curable, but she should be able to have chemo to slow it down. GET THAT SECOND OPINION.
I am sorry that this is happening to you and your family.