I am so sorry to hear about Maggie's passing. What a shock that must have been. My sincere condolences.
My name is Rebecca. I am a veterinarian and will do my best to help.
I see staging was done when the decision was made to do lobectomy and chemo. What tests were done to do the staging: abdominal ultrasound, chest Xrays, brain scans?
What kind of lung cancer did she have?
When we see things like head tilt, her legs giving out, and then the final terrible episode of collapsing and dying, it can be due to neurologic (brain and spinal cord) problems, or heart problems (weak or irregular heart beats that cause a decrease in the oxygen supply to the brain). Blood clots and blood pressure abnormalities may also be the problem.
She may have had a heart problem, and was having episodes of "syncope", not enough blood and oxygen to the brain. Another possibility is that her cancer spread to her brain and caused these episodes, and her death. It would help to know what kind of lung cancer she had; some lung cancers are more likely to spread to the brain than others.
I am so sorry for your loss, my deepest sympathies. Please let me know what else I can answer or help with. Rebecca