To achieve the perfect Jew Score, one must be, in one word, awesome. Oh, and Jewish. It's a Jew Score, after all. So, two words: awesome and Jewish.
So sadly, we cannot award Raoul Wallenberg the 15. But we'll try to get close.
For Wallenberg is beyond awesome: during World War II, the Swedish diplomat saved thousands upon thousands of Hungarian Jews by issuing them Swedish passports.
(Just don't tell the Soviets that Wallenberg was awesome. After the war, they detained him, and he died in captivity. What a fucked up country the Soviet Union was.)
But alas, Wallenberg was not Jewish. Oh, do we ever kvell for him, so here goes a K Score of 5, but, sadly, the O and the I have to be pretty low.
Except... his name does end with "berg", doesn't it? Sure, that's not exclusively Jewish, Swedes have that as well, but sounds kinda Jewish, right? Perhaps enough to earn an extra O point?
And what's this? His great-great-grandfather was Jewish? Well, that's worth an I point right there!
So, once we add it all up, we have a 10. Not a perfect 15, mind you, but as high as we'll ever go for someone with just a smidgen of Jewishness.
Hard to deny someone so awesome, after all.