I believe the proposal that FDR rejected was to bomb the railways serving the death camps. He claimed that we needed the bombs elsewhere.
Why do I suspect that if FDR’s family members were endangered, he would somehow find an extra bomber or two to bomb the damn railroad tracks?
Why were we bombing Dresden instead, a non military target?
B17’s or B24’s taking off from England or Libya (or maybe Sicily after mid 1943) to bomb Auschwitz in southern Poland could possibly have continued on to land in Russian terrority (shuttle mission). Several of those types of missions were flown with reduced bombloads. But they had heavy losses and our Russian “allies” were not very cooperative.
Also, the early Ploesti raids in Romania by B24’s from Libya killed a lot of American bomber crewmen and did very little damage to Ploesti. The Ploesti raids might have been a factor in FDR’s decision.