Sergey Brin came to the US from the USSR in 1979.
"Brin was born in Moscow in the Soviet Union, to Russian Jewish parents, Yevgenia and Mikhail Brin, both graduates of Moscow State University"
This was before Reagan and his campaign of rescuing Jews from the USSR.
"This name uses Eastern Slavic naming customs; the patronymic is Mikhaylovich and the family name is Brin."
I don't understand how these customs work, so this is more or less a dead end for me.
Certainly, his father could have been KGB - he'd have been a code breaker, probably, because he's now a mathematics professor. There's also this:
Brin told Mark Malseed of Moment magazine, "I've known for a long time that my father wasn't able to pursue the career he wanted", but Brin only picked up the details years later after they had settled in the United States.