Thanks for using the forum.
I can understand your concern about another surgery, especially after all your father has been through in the past year. Is it possible to conference with the lung doctor and your father's surgeon? Most surgeons will not want to take an unnecessary risk if a patient is not cleared for surgery by another specialty. Is it possible that either the surgeon does not know the full extent of your fathers lung issues, or that the lung doctor is not aware of the full extent of the surgeons concerns regarding the more extensive emergency surgery? If the two doctors were to consult they might be able to agree on an action plan that is safest for your father. Additionally, if you or your father is still not sure which is the safest route, it might not hurt to get a second opinion.