Drainage due to infections: part of broken femur died. ist it necessary to removed? or can it be treated through iv antibiotics?

Have to do surgery: Dead tissue, died femur has to be surgically removed, antibiotics only controls infection, not revive your dead femur.

Surgery, probably: It sounds like you have osteomyelitis (bone infection) in a bone area that died because it no longer has a reliable blood supply. Antibiotic treatment alone usually will not cure such infections; surgery to remove the devitalized (dead) bone probably is necessary. If that is what your doctors advised, I think you should go along with it. Good luck!