A slimmer Busch approached the 1934–35 season, having taken a four-week cure at a sanatorium in Karlsbad (Karlovy Vary). ‘How many tons have come off?’ inquired Fritz from Buenos Aires. The answer was seven kilos. Visits to the East Bohemian spa town, nestling in beautiful countryside, were made virtually every summer during the 1930s. Frieda went with Adolf to take the waters and lend him moral support, as he was too weak with hunger to do any composing. Towards the end of each cure, Irene and Rudi arrived in the car to stay for a couple of days before taking their elders home. ‘At dinner, all the other guests looked at us with disgust and almost hate’, Irene wrote, ‘because we got a full, regular dinner, while everyone else was starving and looking at the neighbors’ plates with envy.’ On this 1934 visit George Szell and his parents were staying at the same sanatorium, so Busch and Szell amused themselves by pushing slips of paper with obscure musical quotations under each other's doors. As Irene recalled,

At Bruno Walter's request, Busch joined the Association in Aid of German Scholars in Exile; and he did what he could for other refugee organisations. In Basel Frieda organised tableaux vivants of four episodes from The Sleeping Beauty at the Konservatoriumssaal, in aid of emigrant children: Björn Andreasson narrated, more than 100 children took part and the Quartet provided the music, with Irene sitting in for Doktor – they played Bach, Haydn, Mozart and Mendelssohn movements, as well as a march specially composed by Busch. A more orthodox Geneva recital saw the Quartet return to the Ravel F major after a seven-year gap, for their first performance of it with Herman: it was heard between Schumann's work in the same key and Beethoven's Second ‘Rasumovsky’.