It's my understanding that Nuvigil is cheaper than Provigil. If that's true, try that tack first.
Also, there is some med whose name escapes me that must be mixed, but is basically Provigil. Someone, jog my memory, please.
Finally, these meds are antii-narcoleptics. Your friend might have to go through a few other of these to show they didn't work, etc., to finally to be allowed the real deal. Insurers make us go through these hoops but it might be worth it.