"John (2), 1707; probably married Avis, ... In his will dated February 5, 1747, probated July 5, 1749, he names his sons, Andrew and Zebulon; his wife, Avis, and Peter Bowne, executors of the will, ..." Also had a son Bedent.
The author concludes that his sons Andrew and Zebulon were of legal age in 1749, since they were executors of their father's will along with their mother. Possibly the author misread the document and they were mentioned but not as executors.