My mom has been diagnosed with bone marrow cancer, her haemoglobin was 69, they won't be giving her any treatments she's too frail.how much time left.

Depends..: There are many types of bone marrow cancer, and time left depends on the type. If you are referring to myelodysplastic syndrome, the prognosis differs widely based on the prognostic risk factors such as genetics, cancer cell count and cell lines involved. It can be as short as few weeks to months and as long as many years. Consult with your hematologist..

Need more info: You probably mean 6.9 g/dl? There are several types of bone marrow cancer such as leukemia, myeloma etc. Treatment depend on the diagnosis, her age, her general status etc. It is hard for me to predict her life span without knowing the diagnosis.

Varies: There are more than one cancers that can arise in the bone marrow. Most likely she has acute leukemia which runs a rapid downhil lcourseand it can be over in a matter of few weeks. Myeloma is another bone marrow/bone cancer which can alst a few months. But a lot dpends on her blood counts especially her white cell and platelet counts which when low can lead to serious trouble in a matter of days.