I am sorry to read about  your Nan.

I can't comment about the secondaries in bones, but my partner had secondaries in his liver.  I can well understand your sense of denial about the prognosis when you can see your Nan still mobile at the moment.  My partner was only diagnosed with cancer (unknown primary) as a result of a CT scan 2 1/2 weeks before his death in June 2019, after being admitted to hospital due to becoming jaundiced.  He discharged himself from hospital and when he first came home he was mobile and eating and drinking; although I knew the cancer was incurable I assumed we were looking at months at least. However, his deterioration was very rapid which was shocking for me,  BUT probably for the best for him.   He became sleepier and weaker  but stayed mostly comfortable until  he died of liver failure; if he had survived longer he would have experienced more pain due to the cancer tumours themselves.

Personally I don't believe you can fight against getting weakened by liver failure (as indicated by jaundice).  It is heartbreaking to lose a loved one, but when they are terminally ill we have to hope for as much comfort and as little pain for them as possible, this is more important than the length of their survival.  

Wishing you some quality time with your Nan.

Thank you for your response and I'm sorry to hear about your partner too.

It's definitely not what I wanted to hear regarding the rapid deterioration but thank you for being straight with me. I'm living in hope and praying for a miracle which probably makes me sound really stupid, I just cannot bear the thought that we have weeks left. But I agree completely with what you are saying with regards to comfort and I want it to be as painless as possible. 
 

This vile disease destroys so many lives. 

My nan in April 2020 was diagnosed with liver carcinoma cancer and lung cancer.  They gave her false hope by saying she can have operations than changing there mind and tried her on chemo tablets for couple weeks . She ended up getting a septis infection and having a heart attack  so they took her of the tablets . The doctors gave her 6-7 months to live and she is still with us . They said there is nothing more they can do ? But maybe she could take steroids to help build her up  or radiotherapy treatment .They haven't bothered to keep in touch throughout the process . Pals never really helped.  I feel like its ageism , she is 72 years old . All this money is payed for cancer treatment and they could do more . The last oncologist she saw a couple weeks ago said she is doing really well for someone who has her cancer and didn't expect her to be walking or see the way she is . 

So have hope,  don't believe everything the doctors says . They cannot predict the future.  They go by figures and percentages  . Make Christmas everyday , and don't think to much about what the doctors say  .

Best of luck x