The vast majority of Ruthenian (GC) Catholics outside of their European homeland are found in North America. In the 19th and 20th centuries, various Byzantine Rite Catholics arrived in the United States, particularly in coal mining towns. The predominant Latin Rite Catholic hierarchy did not always receive them well, being disturbed in particular at what they saw as the innovation, for the United States, of a married GC Catholic clergy. At their persistent request, the Sacred Congregation for the Propagation of the Faith applied, on 1 May 1897, to the United States rules already set out in a letter dated 5/2/1890 to François-Marie-Benjamin Richard, the Archbishop of Paris. These rules stated that only celibates and widowed priests coming without their children should be permitted in the United States. This rule was restated with special reference to Catholics of the Ruthenian Church by a 3/1/1929 decree, which was renewed for a further ten years in 1939. Dissatisfaction by many Ruthenian Catholics had already given rise to some groups placing themselves under the jurisdiction of the Russian Orthodox Church in America in the 1890s. In 1938 the American Carpatho-Russian Orthodox Diocese was created when 37 Ruthenian parishes were received into the jurisdiction of the Ecumenical Patriarch.
You are getting misinformation from your family, because they themselves are not clear about this matter.
This is not to say that your Rusyn Grandparents were not Russophiles or Muscophiles. Just google PRO RUSSIAN RUSYN and you will find loads of historical explanation why this was. Today appx 70% of the members of Russan Orthodoxy in the USA are in fact descendants of RUSYN Immigrants. They were not Russian before turning to Russian Orthodoxy. They were just Greek Catholic Rusyn that politically became pro Russian and converted to Russian Orthodoxy.