its more general cultural stuff that even i got from osmosis. like pastrami on rye, the appeal of a bagel with shmear, various yid words. hed know about the baby dick suxkinf from being terminally online. at best, he likes an obscure cohen brothers movie about being jewish.
but he didnt understand the few goyim jokes that've been around since the 80's and that's suspect. maybe he has a chinese mother (which would mean he's not jewish)