I'm baffled that insurance won't cover Keytruda for NSCLC.
His biomarker test showed between a 1-49% chance of Keytruda working. Insurance wont cover it
His case would be second line, after platinum-based therapy failure: Keytruda is approved for that case even when patients have as little as PD-L1 expression on at least 1% of tumor cells. For first line, in the metastatic setting, is harder: patient has to have expression of PD-L1 on at least 50% of tumor cells. But for your husband's brother, this is second line.
I would search and contact some NSCLC advocacy group. Or try just Merck --Keytruda's manufacturer- legal team to help. Merck has been/ is quite wonderful to help with pembrolizumab *even* to MSS CRC, so imagine...
Here: Merk program to help access to Keytruda (pembrolizumab, anti PD-1)https://www.merckaccessprogram-keytruda.com/hcc/ https://www.keytruda.com/keytruda-cost/
And he can always go for a trial with it.