What thrilling response does Paul receive into his letter regarding Eduard Keller?

Paul receives two responses to the letters he writes. One letter says that Keller died in 1944, which corroborates the information he discovered in the Adelaide library. The other letter is from cellist, Joseph Henisch, who says he played trios with Keller before the war, and he is happy a biography is being written about this prize pianist and teacher. Paul, wasting no time, packs up his things and takes the next ferry to Vienna.