It's rather an unknown thing of how long you have as some cancers are overly aggressive and some are quite compliant with treatments. With time and treatment your oncologist would be able to give you a more informed answer.
As well as treatment by oncology ask your doctor about turmeric golden paste, golden milk and cannabis oil. They may help a bit.
Just put your faith in your doctors to do what they are paid for and you just live your life as best you can and cherish your family. You may find you are remarkably adaptable to an adjusted lifestyle with treatment and things aren't quite as dark as they seem atm. <3