My father's great grandfather, Abraham Sonnenschein (b. ~1832 - d. ~1860) lived in Balassagyarmat
Abraham's wife was Henrietta Felsenburg, daughter of Marianna (Miriam) Lerner (~1784 - 1831) and
Moses Felsenburg (1772-1849).
Knowing that most Jews in a community knew each other, Ferencz Weisz most likely my father's family!