FDR died in April. Patton died in December.
Doubtful FDR was involved.
FDR allowed a lot of injustices to US citizens, including the imprisonment of many Japanese Americans(I was born in 1942 and am a staunch America and believer in the Constitution,BTW)and the placing of individuals he deemed a threat to his agenda in an insane asylum for the duration of the war. He wasn't very nice. However, he did die before Patton died and Harry Truman was in charge then, a much nicer fellow , a democrat yes, but not a total socialist such as FDR(Truman's biggest failure,IMO, was not going along with Douglas M's plan to nuke the Chinese army during the Korean war). Truman wouldn't have condoned any covert operation against Patton, he would have simply fired him, as he did MacA. FDR might have gone alone with it since he was a total a**hat.