In 1880 the family lived in Alachua County, FL. In the U.S. Census of the same year, the young man in question was 15 yrs old and listed as attending school with his siblings, strongly suggesting he was not intellectually or physically challenged at that time (when there was no Special Ed). The father died in July 1899 in NJ. Between 1880 and 1899, they had moved to NJ. I don't know exactly when, but the 1885 NJ State Census does not show the family in NJ, except for the oldest son who moved to NJ some years before the rest of the family followed. The best guess is that the family move occurred between 1885 and 1889, the time of the commitment. Unfortunately, as we know, the 1890 U.S. census was mostly destroyed in a fire.
Smyrna, DE USA