This James Hewlett entered Christ Church College, Oxford, as a commoner and matriculated on 3 May, 1662. He was tutored by Benjamin Woodroffe who was a particularly noted tutor and later chaplain to Charles II, and by Arthur Squibb who later became vicar of Netherbury in Dorset. Hewlett himself was a tutor between 1669 and 1672, and a Proctor of the University of Oxford until his death. Enquiries made by a descendant, Leonard Hewlett, in 1922 to the London College of Arms revealed that the arms were borne by the ancient Irish family Hewlett, one of whom was buried at St. John's Church, Dublin on January 26, 1667. Also, a member of the family, George Hewlett, held the Office of High Sheriff of Dublin in the middle of the 17th century.
Further research is required to validate the above.
And, it is within the realm of possibility that Captain Hewlett and Rev. William Hewlett, father of James the Blue-Coat boy, were brothers as they were about the same age. John Howe was chaplain to Oliver Cromwell, and the introduction to his biography was written by James Philip Hewlett who was an admirer of his.