Robert Getty certainly wasn't dead by 1870. The family actually moved away. His wife and children were still in Queens County, NY in 1870, and I assume he was then preparing their new residence before sending for them. At any rate, they are listed in the 1880 U.S. Census of Harlan County, Nebraska (Spring Creek Township): Robert Getty, aged 69, retired carpenter, born in Scotland; wife Emily Getty, aged 64, born in Pennsylvania; and son Rodmond (="John R." in earlier censuses) Getty, aged 30, farmer, born in New York. They were all living with the daughter Emily (born circa 1842), who was married to John Burtchet.
When the 1885 State Census of Harlan County, Nebraska was taken, Robert Getty was still living: Robert Getty, aged 74, born Scotland. He died sometime after this, but I don't know exactly when.