Thanks to all-time suggestion champion La Jolla Moishe for the terrific lead. This is Moishe Oofnik, Oscar's cousin:
You will note that Oscar has another cousin, Roscoe, who lives in Poughkeepsie. Roscoe doesn't seem Jewish. But we're willing to bet that he is related to Oscar's father's (non-Jewish) side of the family, while Moishe is from the mother's (Jewish) side. Seriously, look at her:
Can she be anything but Jewish?