In New Jersey.
There were two people named George Chrisophe Tjaden. One of them was the father of Francoise Tjaden. The other one was George Jr., the younger half-brother of Francoise.
This is probably the younger brother of Francoise. In fact, Francoise was living in that household when this little boy was a baby. She later got together wth her dad's employer, Willem K. Crans, and moved to St. Joseph, Michigan, where they raised three children.