It is still pretty strange, looking up both the parents name Yuhas seems to be predominantly occurring in Ukraine, and the maiden name of his wife Bukatko seems also to be from that area.
It was the 1870s when the parents was born, and looking at a map of the Austrian kingdom that was formed 1867 Croatia was part of this kingdom and even parts of Ukraine (Galicia, Transcarpathia, and Bukovina) which explains why they're registered as Austrians in the US census.