Boston King and his wife Violet were among those who fought for the British and had to flee the country when the colonists won the war. Both are included in the "Book of Negroes". King escaped from a cruel carpenter who held him in bondage. Once he arrived in British controlled territory, he faced a smallpox epidemic. King became infected but miraculously survived. Blacks who did not recover were taken from camp and abandoned to die in the woods. King fought for the British, but had to escape captivity twice. The first escape was from a Loyalist who attempted to sell King back into slavery. The second escape was from a whaler that captured the pilot boat where he served. As the tide towards the colonists, King and his wife sought refuge behind British lines in New York City, the last major port controlled by British.

The rumor arabesque that Washington negotiating with the British was pushing for slaves fighting for the British would be sent back to their owners and returned to slavery. The British complied a list of blacks who joined British forces prior to signing of the treaty that did indeed return blacks to slavery. The 3000 people on that list were under British protection and would not be returned the the colonists. They were issued certificates of freedom. Most of the Loyalist blacks were sent to Nova Scotia. Nova Scotia proved far from ideal as British failed to deliver supplies to the towns were the black Loyalists lived. King was able to obtain passage to Sierra Leone for he and his wife. By this time, King had become a preacher. He was tasked with preaching to and converting Africans. Facing a language barrier and lacking teaching skills, King traveled to England to become educated to be a teacher. This enabled him to serve his students better. He goal was to teach English and Christianity

There are real and powerful stories detailing the lives of the black Loyalists.

https://www.pbs.org/wgbh/aia/part2/2p60.html

oops, being a sloppy scholar myself, I did not check out the bottom of the wikipedia page til now, and I see this, records pertaining to him owning African slaves, he advertised the sale of one:

Family and slavery

Fraunces may have had a first wife named Mary Carlile.[19] He married Elizabeth Dally at Trinity Church, Manhattan on November 30, 1757.[46] They had seven children: Andrew Gautier Fraunces, Elizabeth Fraunces Thompson,[47] Catherine Fraunces Smock, Sophia Fraunces Gomez, Sarah Fraunces Campbell, Samuel M. Fraunces, and Hannah Louisa Fraunces Kelly.[note 8] Andrew G. Fraunces worked in the U.S. Treasury Department until 1793,[49] and published a pamphlet denouncing Alexander Hamilton for his financial dealings.[50] Some of the other children ran hotels or boardinghouses. Samuel M. Fraunces, served as executor of his father's estate,[51] and was listed as an "Inn keeper" at 59 South Water Street in the 1795 Philadelphia Directory.[52]

Fraunces employed servants, including indentured servants, and held enslaved Africans in bondage.[19] In 1778, he advertised the sale of a 14-year-old male slave.[53] The 1790 United States Census for New York listed him as a free white male, with four free white women, and one slave in his household.[54]

and this on the portrait illustrations. Which tells me, as I suspected, that it is quite possible that the oil portrait is not correct. But that the little sketch most probably is correct! He very probably looked just like that ink sketch, and the original sketch may very well still be with his family:

Portraits

The oil-on-canvas portrait at the top of this article was purchased by the Sons of the Revolution in 1913, announced at their December 4 annual meeting,[note 9] and has been displayed at Fraunces Tavern ever since.[60] It came from the collection of Anna E. Macy of Riveredge, New Jersey, and was offered for auction at Merwin Sales Company, November 17, 1913.[60] Auction catalogue description: "Artist Unknown / Colonial Period / Portrait of Samuel Fraunces / Canvas. Height 29in: width, 23in."[60] Art forensic experts examined the portrait in October 2016, and concluded that it dated from the 18th century.[60]

The ink sketch at the top of this article – undated, inscribed: "from Fraunce [sic] of Fraunces Tavern / J.T.", and attributed to John Trumbull – descended in the Fraunces family.[12]:Appendix 33–34 An engraving from the ink sketch was an illustration in Alice Morse Earle, Stagecoach and Tavern Days (1900), page 184. The illustration was credited: "Sam Fraunces. From original drawing. Owned by Mrs. A. Livingston Mason, Newport, R.I."[61]

A copy of the oil-on-canvas portrait was painted for the Fraunces Tavern restaurant in 2002, and is viewable on Flickr.[62]

Thanks again, you bringing all this up reminded me I knew Adams never owned a slave. So I went in search of any of his opinions on slavery and I found this:

John Adams on the abolition of slavery, 1801

A primary source by John Adams

John Adams to George Churchman and Jacob Lindley, January 24, 1801. (Gilder Lehrman Collection)

On January 24, 1801, President John Adams responded to two abolitionists who had sent him an anti-slavery pamphlet by Quaker reformer Warner Mifflin (1745–1798). In the letter, Adams expresses his views on slavery, the dangers posed by abolitionists (who at the time were mostly Quakers and unpopular religious radicals), and emancipation. Of slavery Adams writes, “my opinion against it has always been known,” noting that he has “always employed freemen both as Domisticks and Labourers, and never in my Life did I own a Slave.” [....]

 

Even a man as intelligent and thoughtful as Adams was wrangling with it.

It was just so helpful for you to bring up the Hobbesian view of things for the point I was trying to make. I firmly believe that people in general really thought differently from us before the Enlightenment. And it was a process of realization, not a lightbulb, in which our founders were major participants. Comes from my study of "the Dark Ages", but no need to get into that here, your paragraph on Hobbes and the idea of top-down authority as the only way to have civilization sums it up well.

My point was not to apologize for slavery but to bring up that people had accepted it for millenia as part of the whole natural condition of things. Like I said, in the end, where it goes down for me: I think it was amazingly brave to challenge slavery at the time. And I think that the challenge of standard Hobbesian way of doing things that our founders were attempting is still something we should be very proud of, because it was participation in the whole process that eventually ended up with a new civilization without slavery. Not to mention freedom of speech and religion and one man one vote. That many of them had mercenary motives or other motives we do not laud does not diminish this for me as it does seem to diminish it for Jolly Roger. Precisely because: you need coalitions to affect revolutions, where many of the participants will not be ideal. Suffice it to say Patrick Henry couldn't have done it alone. I for one am still in awe of what our founders did, and proud of it, even though many of them were no doubt nasty privileged white guys in many ways.