> Thanks to him and his son, Brazil was the last country to abolish slavery.

Nope, there were dozens of countries that abolished slavery later than Brazil. The most recent was Mauritania, in 1981.

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

I believe Brazil was the last country in the Americas to abolish slavery, but far from the last country in the world as a whole to do so.