I left out one point - the baptism was involuntary, having been performed when he was an infant. Had it been of his own volition and understanding the answer could be quite different.
His mother was born Jewish - so he is technically Jewish. The post-natal baptism can be a problem or an asset. Should he want to be 100% RC he has been immersed so he is Glatt Catnolic. Should he wish to retain and reinforce his Jewish identity, he is legally one of the tribe or an "MOT" The stupid remarks of people who judge their fellow man by the shape of a nose, eyes, ears or head or other superficial things unfortunately will always pollute the air and he has to toughen his skin and rise above them. I wish him much mazal and a b'racha.
This fellow should never forget his youthful up bringing as it was based on and old as the Torah itself..
the comments made by Dietz Ziechmann I fully agree with, thank you for your very expressive thoughts.
Judaism is an ethnicity and a religion. Your religious practice is Catholicism and your ethnicity is part Jewish as I see it. And since Jesus was Jewish and Mary is the most famous Jewish mother of all there's really no conflict at all in being all the wonderful parts that you are!
I would be interested to know where in U.S.A. he lives?parents?grandparents?
was his mother Jewish by birth?
It seems good to me that you recognize having something of a Jewish heritage. Being Roman Catholic means having a different psychology. In this faith tradition Jesus is idolized as a god. Yonathan bar Nappaha identified the root of Jewish identity as not practicing idolatry, for its psychological ramifications. This dimension has practical importance in one's daily life. It's not a matter of loyalty or how other view us, it's about how we interact with the universe. This is what distinguishes Judaism from Islam and Trinitarianism: Judaism does not idolize anyone, Moses, King David, Binyamim Netayahu. Anyone, The Israelish portion of the tradition even allows Jews to hold God to a high moral standard at least conceptually. It hope you will not sell yourself short merely for social familiarity and convenience. I good much interfaith work, and strive continually to find common ground with people of other faith and find the good in them as I hope they find the good in me. You have power in your hands.