I think all of the criteria allowing an MD to escape from prosecution under 21 CFR [The part of the Code of Federal Regulations concerning FDA regulation of off-use, clinical trials, drug promotion, marketing, etc, etc.] are pretty well satisfied by antiviral drugs used in treating Ebola patients.
Anyway, unlike 0bama's mythical foot-choppers, every Doc I've ever known would be willing to do anything they could possibly do to save a patient, and damn the regulations.
Does it work? Only one way to really find out...