***** NOT A TEACHER *****
I have read that in the 19th century, many educated people here in the States and in the United Kingdom regularly used "don't" with the third person. Then school teachers kept beating into students' heads that the correct form should be "doesn't." So today, if a person says "He don't," that person is considered by many people to be (pardon the word) "ignorant" or "poorly educated."
1. Was that "bestseller" set in the 19th century?
2. Does that "bestseller" describe a "poorly educated" person?
3. From 1913 - 1921, our president was Woodrow Wilson. I have read that he regularly said in private things such as "He don't," but in public he was always careful to use "doesn't."