There were times when people believed that George Washington would free his slaves. It was also believed that he would try to free the slaves after the American Revolutionary War.
However, that did not happen. This was a time when farmers who owned large areas of land would own slaves. Some of the slave owners were kinder than others. When George Washington drafted his will, he asked that his slaves be freed no matter what age they were when he and his wife Martha had died.
Instead, about one year after George died, Martha freed the slaves. She died about a year after that. So, the story about Washington freeing his slaves after his death was somewhat true but it was also after his wife died too.