I'm a lineal descendant of William Willett, of Prince George"s County, Maryland and his wife, Mary Griffith. Some years ago Mary Louise Donnelly published a book entitled Edward Willett, colonial Maryland Pewterer. She reported a contemporary record which indicated that Mary Griffith was the sister of George Griffith. I don't immediately have further particulars. I hope this is helpful.
Best always, Douglas Richardson, Salt Lake City, Utah