Odd. His wikipedia page [0] offers a very different ending. Rather than "went to live in Fort St. Sebastian," it offers:

> According to at least one report, he was taken to a Dutch fortress, Fort San Sebastian in Shama, in the 1750s, possibly to prevent him sowing dissent among his people. The exact date, place, and manner of his death are unknown, though he probably died in about 1759 at the fort in Chama in Ghana.

https://en.wikipedia.org/wiki/Anton_Wilhelm_Amo

The German and French wiki articles have yet other variations of his life's end and year of death, as do a few other articles on Google's first page result. Just spitballing here, but digging into the details looks like a low hanging fruit for someone in need of a thesis topic for a degree in History.