We have hundreds of profiles on this website of people with one Jewish and one goyishe parent. As a rule, those get an I Score of 3... but the verdict differs. Prepare for a deep dive!
"Jew": They consider themselves Jewish. End of. Failing that, there is no evidence of them practicing another religion.
"Borderline Jew": It's not exactly clear. Maybe they celebrate Christmas or something.
"Barely a Jew": They worship at the altar of a goyishe deity, usually Jebus. Or there is this: "I am not Jewish".
That's from French actor/director Mathieu Kassovitz. His father is a Hungarian Jew. His mother, a French goy. You might remember from that famous Manic Pixie Dream Girl movie from 1990s, "Amelie". (He is not Amelie.) Or from a bunch of... other French stuff. No, you probably don't remember him.
Here's the full quote: "I am not Jewish but I was brought up in a world of Jewish humor".
Are we sure we can't push him up to "Borderline Jew"?