Curtis was the oldest of nine children, he never married and most of what we know of him is through his connections with other people. At the beginning of the Revolutionary War he was 21 years old, his father immediately entered the war as a surgeon and his brothers Andrew and Isaac also enlisted but Curtis remained home to care for the family.
from "The Reverend John Graham and His Descendants" by Helen Graham Carpenter Monastery Hill Press Chicago 1942. Written in incredible detail 507 pages long, many pages foot noted with source detail. The Graham family was for the most part, doctors, lawyers, and many reverends.
On Curtis it went on to say, but I didn't see the need to add, was years later his brother Andrew Graham L.L.D. a successful attorney from New York erected two tombstones, one for his father Dr. Andrew and the other to be shared his mother Martha and his brother Curtis. On the later were two mistakes, Curtis was 53 not 44 when he died and Martha died in 1825 not 1826.