Parkman describes the man this way:
However, it was begrudgingly recognized that Vaughan would have to be included in on the colonial expeditionary force which was being sent to take Louisbourg in 1745. Of course, Vaughan being Vaughan volunteered to lead; an offer which was politely and quietly declined by all involved. One gets the impression that when ever Vaughan left a group of people there were winks and smiles all around. Shirley, for one, considered Vaughan a "whimsical, wild projector." Nonetheless, though he had no special command, Vaughan was, for the purposes of the expedition, commissioned as a lieutenant-colonel. Vaughan did prove to be helpful to the campaign; he "spent considerable time and energy recruiting scores of volunteers." So, too, it is plain from the record that he tirelessly worked his men in the laborious work of the siege: he drove them on to dig trenches and to build gun batteries. Throughout the piece, however, Vaughan felt "his fellow officers' jealousy and slights."
Vaughan was very keen on bringing the news to England of Louisbourg's capitulation; and, indeed, there might have been some sort of promise made to him in this regard earlier on in the process. When the French laid down their arms, Pepperrell and Warren didn't spend too much time thinking about the matter; they dispatched one of Warren's own, Captain Montague in the 40 gun Mermaid to bring the news to London.2 Vaughan took this as yet one further slight and responded by arranging for his own vessel to bring him to London; presumably he arrived a little late with the news, at any rate, it seems he didn't get much of a reception.
While still in England, Vaughan contracted smallpox and died in 1746.
 A Half Century of Conflict (vol. 2), pp. 65.
 NSHS, #30, p. 38.