I quote Hamodia, “Inyan”, 28 Tammuz 5779 (July 31, 2019), p. 37:
[Rabbi Shlomo Halberstam convinced Holocaust survivors to join his kehillah.]
A Bobover talmid chacham once told me that he was never totally sure that his father, after surviving the traumas of Auschwitz, really believed in Hashem again. But, his father definitely believed in the Rav, who convinced him to be frum again. His father, zichrono livrachah, left behind generations of maaminim bidvar Hashem.