AFAIK Hitler was counting on the Alliance between the anglo-americans and the soviets falling apart before Germany ceased to exist. I bet FDR's death brought him one last ray of hope.

A continuation of the war effort after Germany's fall, this time against the Soviets, would not have been any kind of cakewalk for the angloamericans. My impression is that there were many more forces deployed in the East than in the West in Europe at the end of the war. Remember also that the US was still planning for a full-scale ground invasion of Japan into 1946 at least.