Briskers and Proof

The Brisker Rav in Hilchos Korban Pesach argues the Nevi’im had to play musical instruments, and the Bnei Chaburah sing by mouth during Korban Pesach.

Someone once came to him and brought him proof from Josephus who seems to describe the same thing actually happening in front of his eyes. The Brisker Rav responded that he doesn’t need the proof, since he has Rishonim, etc. on his side.

Fine, so יהודה ועוד לקרא.

What I wonder is what he would say if Josephus was shown to disagree with his explanation? As a Brisker, there is a great case to be made he would ignore it, although the Rishonim themselves sometimes quote Josephus as proof…

מטמאיך לא טמאוני ואתה טמאתני?!

UPDATE: See the correction here.