Do you have all of your ancestors US records? Did he have social security numbers? Was he naturalized US citizen? Did you find his church marriage record?
Yes, it is possible the church records would be in Russian or Latin - the church language.
Have you posted on Poland's Ancestry board?
BRZOZOWSKI surname holders in Poland:https://nazwiska-polskie.pl/Brzozowski
map of Poland's wojewodztwos:http://www.geneteka.genealodzy.pl/