Spine mets detected

My father has been fighting melanoma since Fall 2017. Started under left thumbnail and very small amount in some lymph nodes in left armpit so i think it was stage III at the time. Had upper joint of thumb removed and a couple lymph nodes removed. No immunotherapy. in Fall 2018 detected more in his left armpit lymph nodes so he had surgery to remove all the armpit lymph nodes and was put on opdivo. Tolerated well but developed red spots on back of left arm around april/may. He was put on Opdivo/Yervoy combo and the spots almost disappeared after the first treatment, all went away and he had full course of combo. Developed colitis in September 2019 and was put on steroids through December. Doctor thought he was too weak to put on opdivo alone so waited 4 months between Jan – May 2020. They found a suspicious spot on his left lung in the May scan so they did another scan at the end of June and found that it was melanoma and size had doubled (still small). He also has skin melanoma on back of arm near left armpit. Dr put him back on Opdivo and he got 3 treatments. Had a bad fall early September and started to get back pain which we thought was from the fall. His pain continued to get worse and the last week of September he lost 10 lbs. Went to UVA to get a scan and they found stress fractures in some of his back vertebrae and left kidney was swollen. This past Monday they admitted him to the hospital and found that the lung melanoma had increased in size again but still small so plan was to do radiation on lung and surgery/radiation on the skin melanoma near his left armpit.

I probably got my hopes up way too much because i was reading about how radiation can help jump start immunotherapy sometimes so was hoping that would kick off the opdivo he had the last 3 months. Late wed in hospital they did full body MRI and results Friday morning were bad. About 1/4 the way up his back there are multiple small spine bone mets and one that is larger (not sure about size). Also has a couple very small spots in his neck spine bone.

He is starting 5 day radiation treatment this upcoming Monday to atleast help with controlling the growth of the tumors and hopefully to help with the pain. Of course i want answers now and am thinking about Post radiation treatment options or combo options. For now the focus is just on getting radiation for the spine and lung mets.

Sorry for the long rant but I wanted to give his history. He is 75 years old so I am worried that the Dr might not want to try treatments that have higher chances of side effects and bc of his age and recent weight loss. Also think he will be more limited with any clinical trials that are out there bc of age. If the radiation helps and shrinks or eliminates the mets and he gets some of his strength back should immunotherapy be considered? Should he try Keytruda instead of Opdivo? Can he get one or two infusions of Yervoy again?

I have been reading stories in this forum the past 2 days and they have brought hope and support in this moment. Thank you.