He was a Jew (his native language was Yiddish, although he did not use it in his adult life) working in the USSR. So, either use the official designation used at the time - "soviet citizen of jewish origin", or just abbreviate it to "soviet".

This is precisely the reason not to go there. When the hosts refuse to assert their culture, the "guests" start to assert theirs. This has been happening everywhere and some people, e.g., aussies, are starting to wake up.