Lung Cancer and Bone Mets

Hi, recently my elderly frail 77 yr old mother was diagnosised with a lung tumor which is highly suspicous and highly expected to be lung cancer.  She has COPD and has been on continuous oxygen for 9 years.  The CT scan also noticed a "deteriation" on her spine which was either bone mets or osteoporsis.  I found it appaling that they couldn't tell the difference.  Apparently, if it's spread her prognosis time is much different.  Because of her frailness she is not a candidate for chemo and even for the biopsy to confirm 100% whether it's lung cancer is a little risky.  They would do a brochoscope for the biopsy but can't put her under for it but could sedate her but there's also a risk with the oxygen levels going down with it.  They would do raditiation but said it likely wouldn't be of much benefit and there are side effects and risks even with that.  Are there any blood tests that assist in diagnosing lung cancer or even bone mets?  I know there are CA markers for some cancers, are there any for lung cancer?