Individual Details

Moses was born in 1705 in Sudbury, where his father Samuel had been a long-time resident. He is the oldest child of his father Samuel and Samuel's second wife, Abigail.
Moses is listed in the book, Walter Allen of Newbury, Mass., 1640, and some of his descendants, on page 5, with the words 'nothing further known.'
Moses is mentioned by name several times in his father's probate documents, mostly from 1720.
Moses was only 15 years old at the time of his father's death, so the court appointed him a guardian to be sure that his interests were addressed in the division of his father's property. Guardianship was addressed for his two younger siblings as well, all in the same file.
12 Feb 1722 - William Johnson was appointed guardian of Aaron, a minor in his 16th year and Abigail in her (unreadable age), two children of Samuel Allen late of Sudbury. Moses not mentioned and perhaps already deceased?
Joseph Dean did present a report "Guardian to Moses Allen Minor dec'd (a son of the late Samuel Allen...) Filed by John Allen, 30 Oct 1722.
In this guardianship file, Abigail, who was a single woman living in Dedham in 1732, wrote a letter of dismissal for her guardian, indicating that she was "fully satisfied for all the estate of my father and brother Moses, deceased." I don't know exactly when Moses died, but it was before 1732. Both Abigail and her brother Aaron were living in Dedham in 1732, as Aaron married there and had children.

https://www.ancestry.com/imageviewer/collections/9069/images/007552895_00909?usePUB=true&_phsrc=vsT3131&_phstart=successSource&usePUBJs=true&pId=6375199

Birth	9 Sep 1705	Sudbury, Middlesex County, Massachusetts
Death	Bef Oct 1722

Father	SAMUEL ALLEN (1658 - 1720)
Mother	ABIGAIL Williams (1673 - 1714)
Sibling	Aaron ALLEN (1707 - 1754)
Sibling	Abigail Allen (1710 - )