Although he had lost his entire family — including his wife, children, grandchildren, and in-laws and their families — to the Nazis, Rebbe Aharon re-established his Hasidic court in Tel Aviv, where there was a small Hasidic community. Both he and Rabbi Mordechai (who had lost his wife and daughter) remarried, but only Rabbi Mordechai had a child, Yissachar Dov Rokeach, in 1948. Rabbi Mordechai suddenly died a year later, at the age of 47. Rebbe Aharon took his brother's son under his wing to groom him as the future successor to the Belz dynasty.