What Is The Prognosis Of An Elderly Woman With Fractured Pelvic Bone And Advanced Dementia?

My 86 yr old mom fell 12-31 -2014 broke her pelvic bone. has advanced dementia. Dad died 02-25-2014. Mom doesn't want to eat. Drinks a little soda ever now and then. Says she not hungry. Family said no to feeding tube since it seems mom has given up. Just skin and bone now. How much longer do you think she could be with us?