Benjamin was born in the industrial city of Lublin to a large, Yiddish-speaking Jewish family. He attended public school, and after he graduated at the age of 14, he apprenticed at the same tannery where his father was the tannery master.
1933-39: After completing his apprenticeship, Benjamin became the assistant tannery master. After his father's death in 1938, he became the production tannery master. He and his wife, Gucia, lived with his mother at 50 Lubartowska Street. In 1938 the Frydmachers had a daughter, whom they named Ruth. On September 17, 16 days after the outbreak of World War II, German troops entered Lublin.
1940-44: In 1941 the Germans established a ghetto in Lublin. Benjamin's tannery was ordered to produce leather for the Germans. Luckily, Benjamin had blond hair, and by wearing a black leather jacket, he was able to pass for a non-Jew and sneak out of the ghetto so that he could bring the family food. When the Germans began liquidating the ghetto in 1942, Benjamin's mother was machine-gunned to death at a hospital with other elderly patients, and his wife and daughter were deported to an extermination camp. Benjamin managed to escape.
Benjamin made his way to the non-Jewish part of Warsaw. His Jewish identity was eventually discovered and he was killed.