My mum (73yrs old) was diagnosed with SCLC in August 23 which showed cancer in her right lung, pelvis and breast bone. After a successful course of chemo and radiotherapy, she was given a treatment break. When she went for check-up scans in the summer last year it showed that her cancer had grown in her lung and had spread to her liver and brain. She stared another course of chemo - but had to pause the treatment in February due to the chemo causing all of her numbers to drop to 0 (red/white and platelets) her sodium levels and potassium levels were also dangerously low, and she was hospitalised for 11 days.
My mum has recently had another CT scan (couldn't complete an MRI due to being in intense pain) and the oncologist has said the the cancer has grown in her lung and liver again, and is now in her kidneys and adrenal glands. The oncologist has mentioned trying CAV treatment - but is unsure if she can go ahead with it due to her current age and health factors (she has copd, and a previous heart conditions)

What is the likelihood of my mum being accepted for this treatment and if she cannot have this treatment are there any other options?