Upvote:2
Hennig Brand married twice and had at least two children with his first wife and also a stepson from his second marriage.
His first wife was a rich widow and this meant he could spend all his time on research. At least one of the children was a girl.
When his first wife died, he married Margaretha, also a rich widow. She had a son from her previous marriage and he worked for Brand as his assistant.
There is no mention of any other children or their names but it's quite likely that one or two died young as infant mortality was high in those days. One of the sources mentions he had a large family to support but says no more on this.
Sources
How One Manβs Love of Urine Led to the Discovery of Phosphorus