You seem to be establishing a causal relationship between this man’s Judaism and his miserliness. “If he wasn’t a Jew, he wouldn’t be so stingy and I wouldn’t have problems with him” – something like this would be your logic. Judaism of this person has no place in your question, since you are allegedly embarrassed by his stinginess. However, you included his pedigree in your letter. This means that you have grievances not only against avarice, but also against the Jews.
You may not even know about it. The problem with prejudices is that we don’t think of them as prejudices but as facts, and so we never question them. Especially when a person fits our stereotype. Then we are fully convinced that we have living proof before us.
But this has nothing to do with reality, but with our idea of it. The reality is this: among the entire Jewish people there are, of course, stingy people, but also many generous ones, as well as among non-Jews. But don’t think about the non-Jewish miser: “Wait, he’s definitely Jewish and hiding it!” They just think, “Dude, he’s mean.”
So it would be interesting to know why you ended the friendship. Did this person’s Judaism come up as an argument, as in your question? Or did you figure it out yourself?
In any case, if you truly care about this person, you should do more than contact them again. Then you must have the courage to tell this man to his face that you find his greed repulsive and explain it by his Judaism. It won’t be a fun conversation. But honest.