I think that the below, from David Forney, is much more likely:
I did a little digging in my data files and I believe the Henry Forney you are looking for is the son of John Forney and Elizabeth Bixler. John Forney was the son of John Forney AKA John Furry who apparently arrived in America in 1727. He located in Tulpehocken Township, Berks County PA, on a tract of 346 acres of land. He had two sons and two daughters, namely: Michael, John, Rosina (wife of Henry Berger) and Catharine (wife of Leonard Emerich).
Tradition states that John Forney and his wife Elizabeth Bixler settled on the west side of the Susquehanna River. They had four sons and two daughters. The Sons were: John, Jonas, Lawrence and Henry. The first three upon their return from a grist-mill at Sunbury, Pa., found to their horror that the Oneida Indians had killed and scalped their parents and two sisters, and also burned down the house and taken a horse with them. The youngest son, Henry, the Indians took with them to Canada, where he was afterward found. The three brothers buried their parents and sisters under an apple tree and went to Reading, PA.
I have nothing more on Jonas; Lawrence Forney married a Zingmaster. They had at least 8 children. One of the children was Christina Forney born September 02, 1802, she married Charles Druckenmiller; John Forney also no further information; The youngest was Henry Forney as stated was taken by the Indians. The source for the tradition is from a book titled “Historical and biographical annals of Columbia and Montour counties PENNSYLVANIA” published 1915.
The premise that Henry was raised by “strangers” would seem to confirm the tradition