There was an article on Crux by John Allen, a Catholic blog talking about this. The White ethnic Catholics, who were part of the FDR/Truman/JFK coalition, vote overwhelmingly Republican. Recent Catholic immigrant groups from Latin America, Asia, Middle East, tend to vote Democrat. Here is the article from Crux by. J. Allen.
Don't see how that's possible based on the presidential voting results for Roman Catholics. In all but four presidential elections since 1952 they've sided with the demoncrat candidate...and this is well before the massive influx of Hispanic immigrants.
Now, if you want to apply that to just the 2018 midterms I might be in agreement with that.