Sheryl, Im so sorry to read about another recurrence! Im sure this is more than enough for both you and your husband. I would suggest you seek out a second opinion at one of the top Comprehensive Cancer Centers (CCCs). With your husbands cancer coming back so many times a fresh set of experienced eyes would be a good idea.
Without a biopsy, the spot can not be identified as cancerous. Sometimes OC patients will have different "spots" show up in their lungs after going thru rads. Not always does this mean they are cancerous. Its happened to me as well. Having false positives on scans after rads is unfortunately quite common. Only a biopsy will determine what the spots are.
Best wishes with everything!
List of CCCs PS... As a caregiver, take some time for yourself too. Being a caregiver is a difficult job, especially with everything both you and your husband have been thru. Be kind to yourself.