Is it true that the military commander, who gave Joan of Arc her escort to Charles was her Uncle?
No that is not true. Sir Robert de Baudricourt, the Governor of Vaucouleurs, had no family connections with Joan. Her “Uncle” Durand Laxart was one of the first people to believe in her mission. He took her to Vaucouleurs to see the Squire de Baudricourt and when Joan of Arc wanted to leave for Chinon before receiving official permission from the Governor, it was her “Uncle” and his friend, who went with her until Joan decided to turn back to Vaucouleurs and wait for the official permission that she needed.
