12cm Atypical lung tumor!

My 66yr old dad just had surgery to remove massive growth. Originally thought it was small cell, more pathology showed Atypical carcinoid - good as we were about to start chemo! Surgery a big deal but he's sitting up and eating today. Waiting for biopsy results. Afraid there'll be small cell in there too. They're talking about radiotherapy when he's healed. Anyone else know anything about this? It was a huge tumor. Only found when his rib broke twice over summer. They found and removed 4 damaged ribs during surgery as well as lymph nodes. Any advice or info greatly appreciated. Prayers and best wishes for all....