If that was my brother I'd beg him to collect his medical records,hop in the car and head right for one of the teaching affiliates of either Georgetown or George Washington University Medical School in DC.
Having worked at one of the major Harvard teaching hospitals for 20+ years I can pretty much guarantee you that an ID specialist in DC sees 50 times more cases like your brother's than does the doctor currently treating him.
And if Duke is closer to him than DC,the same would go for one of the Duke teaching hospitals.
Both my husband and I agree with you. But I don't think they even consider that they don't have the very best doctors. My sister-in-law works for one and they just think they're the best. We think they're killing him. If I have a chance, I'll suggest the teaching affiliate option. What about UVA?