My mam was diagnosed with lung cancer with secondary liver, lymph, breast and bone cancer she is on 24/7 oxygen. What is her life expectancy?

Also, consider Hospice.

Ruby, only a doctor such as your mother's oncologist, can offer any specific life expectancy prognosis. It depends on a variety of factors, primarily the staging of the cancers.

In addition, it also depends on whether she's getting chemo, radiation, or taking any meds for the cancer.

I am sorry that your family is facing such a challenging situation, but urge you to contact your mother's oncologist for a frank discussion of your mother's life expectancy.