Chemo or T-VEC + Pembro

I’ve posted before about my father who was diagnosed stage IV in January 2020 and progressed on pembro (April-June 2020) and then ipi/nivo (June-July 2020). He hasn’t been on any treatment since July due to toxicities to the combo that have finally resolved – other than SRS to several brain mets. Recent scans have shown significant progression (increased tumor burden in the lungs and new sites of involvement in the liver, kidneys, pancreas, gallbladder). He is feeling generally OK other than fatigue and recently some shortness of breath (due to the lung tumors). The options presented at this point for additional treatment are oral temozolomide or trying T-VEC + pembro. Any insights or experiences into these options? I understand that only 10-15% of people respond to chemo, and only for a short time. And I also understand that there isn’t really any data showing that T-VEC + pembro is effective in patients who have progressed on pembro, but anecdotally there may be success stories. Options for clinical trials also seem limited due to the brain mets, prior toxicities while on immunotherapy, and a history of prostate cancer. Thanks in advance for any feedback or insight.